So John Sevier Tennessee's first governor actually reached out to the French and Spanish about assistance since the Carolinas and Virginia were not providing assistance with troops against Indian attacks. How could French assistance in Tennessee affect future American history? Could Tennessee exist as a French speaking territory?
Sevier had plenty of reasons to invite the French and Spanish to help him, but there is zilch potential of a TL where both John Sevier exists as we know him (well, maybe we can have "Jean Sevier" since he was of Huguenot ancestry) and where Tennessee is French-speaking. However, Sevier was loyal enough to the US, as were many of his compatriots in the Watauga Association. If Sevier needs France (or most likely Spain), then odds are the United States is in much greater chaos than OTL. This could mean a series of "frontier republics" across the Appalachians, like the State of Franklin might evolve into, or perhaps instead the state governors assert authority and the US devolves into a state of affairs like Rosas-era Argentina (I'll note I've always imagined someone like Andrew Jackson seizing power and becoming the American Rosas). But in no case will Tennessee be French-speaking, since the main group of settlers will always be Scots-Irish frontiersmen along with some other groups present in the US South (Englishmen of various sorts, the occasional German, etc.). France does not have the settlers to spare for Tennessee, and if they have rule over Tennessee they will have plenty of other land to send settlers to.
That would be really interesting. How do you think they would get the French people to settle in Tennessee and where in Tennessee do you think they will mostly settle? I think Tennessee could exist as a French speaking territory but I think it would be bilingual sometime in the future. What conflict/war and what year are you talking about that this could take place in?
The only French speaking people would be slaves from Haiti and perhaps their masters. If Tennessee ended up Francophone, the Francophone parts would be by the Mississippi River (West Tennessee) and Tennessee's history would likely involve the majority of it (east of the Tennessee River) being seized in some conflict. West Tennessee is by far the best part of the state for slavery, and the economic strength of its planters (and their descendents, including their political machines) helped dominated the state until the late 20th century. Middle Tennessee has good parts for slavery too, but it's less profitable, and in East Tennessee slavery is even more limited (but obviously present). But the obvious settlers of Tennessee will still be people from Virginia and the Carolinas. There is no reason why they wouldn't be there. There's not enough potential French settlers (in the mid-late 18th century) or Indian elites to empower to prevent these settlers from being there at that point.
I have read that Kentucky pondered whether or not to join the Spanish (the French exiting what ended up OTL USA/Canada in 1763, never to return, except on paper in 1801ish), but not Tennessee. When was this?
It was part of the Spanish conspiracy in the late 18th century, a general movement of certain figures in the area to gain benefits from Spain/France.
Any way you slice it, though, I doubt the idea was to be subjugated by Spain, or France, to the point of being inundated by papists.
Indeed it was not. I like the idea of a "Louisiana" where Tennessee and Kentucky and other borderlands are essentially like Quebec in OTL Canada, which is a plausible result of a more successful Louisiana.
It's a tough row to hoe to make just Tennessee French speaking. If the French are in the south, they're going to have a power base in New Orleans, Mississippi, and Alabama, and aren't going to be easily dislodged by the US. It would mean they never gave up the Louisiana Territory (or regained it from the Spanish and kept it), and developed it. Landlocked Tennessee is NOT becoming a French exclave, nor is it going to be a focal point of a broader region with ocean access.
POD post 1763 is WAY too late.
As I noted, it's a longshot but West Tennessee might be as Francophone as Louisiana, which could also make it a separate state (if/when the US annexes it)--note that the far west corner of Kentucky with Paducah will also be included in this state. This would be huge for the remainder of Tennessee in terms of politics (let's ignore butterflies for a minute), since without West Tennessee (including it's infamous Boss Crump machine), the state could much more easily swing Republican in statewide and national elections unlike the rest of the South. And even pre-Civil War this would be huge, since Tennessee would likely be neutral in the conflict (but West Tennessee part of the CSA), which makes logistics even easier to invade the Deep South (since the Tennessee River will be easier to overtake).
A Tennessee with only Middle Tennessee and East Tennessee will serve as a target for Republicans to try and break up the "solid south". It's capital may well remain Knoxville, although Cookeville (close to the center of TTL's Tennessee) or maybe Murfreesboro (center of OTL Tennessee and state capital for several years) may be the state capital. I think Cookeville in this case would be the best choice of state capital (it's in the middle of Nashville and Knoxville which will be the two major cities in the state), although it may end up like Frankfort in Kentucky (even if it's no doubt slightly bigger than OTL).