Thanks you for the outline, that helps clear things up, though its an amazing tangle of rights and shows!
Well, as far as the Doctor who timeline goes, its very simple!
We start with Colin Baker, right?
Baker regenerates into Lenny Henry, who plays the Doctor in a series of sketches, but is almost certainly a non-canonical Doctor, or possibly an alternate.
Colin possibly regenerates into Benedetti, it's not clear what happens exactly, but she's the next... although its possible that she might be a regeneration from the end of the Doctors life, moved forward in the line.
Benedetti's fan films may be canon for Benedetti, or maybe not, depends on which fan you're talking to, and how much of a BBC purist. It doesn't help that the official BBC series referred to the fan film adventures.
Benedetti is succeeded by Joanna Lumley, who may be either a new regeneration, or an alternate version of the Benedetti Doctor. She appears first in the Nightmare Machine as an alternate version of Benedetti, but the issue is fudged for her appearances in Dark Dimensions and Curse of Fatal Death.
The ITV K9 may be in continuity with Doctor Who. Or it may be a separate continuity. Again, depends on how much of a BBC purist. But there's a lot of free borrowing from the BBC show, and some references.
The Australian K9 series is even more tricky. A lot of the Doctor Who elements were shed and the series was revised somewhat. So there's debate over whether the Australian K9 is in continuity with the ITV K9. So either they're all part of Doctor Who continuity, or only the ITV series, or they're three different continuities.
Benedetti's Wanderer features the Australian K9 and Australian series Monsters, so there's a theory that the Wanderer is actually in continuity not with Doctor Who, but with either the K9 ITV/Australian series, or just the Australian K9 series only.
The adoption of the Wanderer for the Comic Relief broadcast in England, and the re-edit as Doctor Who may have made it part of Doctor Who continuity, and may have dragged the K9 series in through the back door. Or it may be non-canon.
Levine's 'Cold War' mash up is generally considered unofficial, notwithstanding that it, like Shada, is a reconstruction of BBC produced footage. It is, however, the only production featuring Benedetti's death scene. Given Levine's connection to it and the New Doctor, some consider it to be the continuity link between the Benedetti Doctor and the New Doctor. Others just consider it in the New Doctor timeline, separate from the main canon. Others consider it completely stand alone. Around this time, Levine was also separately involved in Downtime, a semi-official production featuring Sarah Jane (but not K9), the Brigadier, Great Intelligence and Yet, so some consider this part of a 'Levine-verse.'
Dark Dimensions is definitely in continuity with the official canonical BBC series, although that still doesn't explain what Lumley is.
David Burton considers himself a canonical Doctor, through both the 'New Doctor' but not everyone agrees with him. We never see him regenerate from an existing Doctor, or regenerate into another Doctor. So it's up in the air. He might be the next regeneration after the Benedetti Doctor, or Benedetti/Lumley Doctors. Or an alternate continuity.
Australia's pick up and re-labelling the New Doctor as the Wanderer may be the same continuity as Benedetti's Wanderer, particularly given the connections both have to the Australian K9 series. But it's not clear that the New Doctor is actually good continuity with the Wanderer, particularly given the additional footage and editing to the season of the New Doctor. Complicating this is that the final season of the Wanderer is dramatically reformatted as an 'X-Files' show. It's entirely possible that David Burton is not in continuity with himself - he may have three separate continuities (The New Doctor, the Wanderer 1 and 2, and Wanderer 3) any, all, or none of which may or may not be in continuity with Doctor Who, Benedetti's Wanderer, K9 ITV/Australia or K9 Australia or some combination.
Rupert Booth is generally considered a canonical Doctor, although purists disagree given that his Doctor was a licensed production, much like the New Doctor. There is also debate over the canonicity of Timebase's fan films starring the Booth Doctor.
The McGann Doctor is completely, solidly, definitively, utterly canonical. For sure. Everyone agrees. We mean it. Except for the Half Human part. This was an official BBC co-production, not a licensed production.
The Robert Downey Jr. Doctor was also definitely canonical, despite being a licensed production. Until Downey got in trouble with heroin and firearms and stuff. At that point, he became retroactively non-canonical.
The Curse of Fatal Death was non-canonical, notwithstanding Lumley's presence. Curse may represent an alternate timeline. In the alternate timeline theory, Curse is in continuity with the Nightmare Machine, where Lumley appears as an alternate version of the Benedetti Doctor, but not in continuity with Dark Dimension.
Because of references to the New Doctor embedded in the script (the New Doctor had a few fans), Curse may actually be in continuity with the New Doctor, but that poses a crazy new set of questions, given that it implies that the New Doctor is the Lumley Doctor's past. This has lead to a fan theory that the since the New Doctor follows the Benedetti Doctor, but is followed by the Lumley Doctor, then the Benedetti and Lumley Doctors aren't alternate versions of each other, but separate regenerations, with the New Doctor (and possibly other Doctors) in between.
Maurice LaMarche's Nelvana Doctor is generally considered non-canonical. Unless someone wants to argue.
The BBC considered the Richard E. Grant animated Doctor to be canonical.... until they relaunched the series in 2005 with Russell T. Davies. At which point Russell decided it was non-canonical. Almost everyone accepts this. Among those that do not, there is some argument as to whether the Grant Doctor might be in continuity with the LaMarche Doctor, since they're both animated series, but this is considered frivolous. Arguing that the Grant Doctor is in canon to 'anything' is actually a parlour game for a certain segment of fandom.
The lack of canonicity or continuity of the Grant Doctor took a blow, when the same actor who played the Master in the animated series played the Master briefly in the new series.
One of the crazier fan theories floating around concerns the Ecclestone Doctor's outfit in the new series - a leather coat, almost identical to the one worn by Lenny Henry through his five appearances. Some fans argue that this means the Ecclestone Doctor has regenerated from the Henry Doctor, and that some or all of the Henry Doctor's appearances are canonical main line. The BBC has, due to the racial politics involved, tried to avoid this subject. But Russell T. Davies is on record as saying that the coats are a complete coincidence. Lenny Henry has publicly speculated. And Christopher Ecclestone claims that it was deliberate, at times he's suggested that his Doctor regenerates from Henry's, but he's usually joking.
Overall, the new series tries not to get into it. As far as the new series is concerned, the Classic Series up to around 1986 is definitely canon, McGann is canon, Benedetti is probably canon, Dark Dimensions may be canon, and everything else is no comment.... except for the Downey Doctor, who is definitely not canon, because of that whole heroin thing.
So there you have it - one single unbroken symmetrical Doctor Who continuity! Or possibly as many as 18 different timelines, with considerable debate as to which is in what. But completely simple!
Aren't you glad you asked?