Could any of these
two work to re make the Situation in Britain
No, with all due respects to posters. It makes simply far too much unbased assumptions, and completly misses what Late Roman society were, including (but not only) what were the relations and integration of Barbarians vis à vis from Romania.
Honestly, I would have nothing against an ASB timeline where Barbarians people turn the whole of Romania as a big equivalent to post-Roman Britain : but it's not something you can pull off realistically, no matter how one tries, or twist.
I can't make it clearer than this : Barbarian peoples very existence is tied to their relationship with late Roman structures since the IIIrd century, at latest. If you get rid of these, you get rid of the others in any recognizable manner.
And to get rid of these structures, you'd need a much earlier PoD that would probably get rid of Roman conquest in first place.
Finally, we can't consider Barbarian peoples as your Tacitus' Ist century textbooks Germans at this point : they were heavily romanized, integrated as a part of Romania, and growingly included Romans since the IVth century onwards.
I think we're rather stuck in this discussion, so I think I'll let at this if you don't mind.