I'm considering flying SFO-LHR (UA), then 3 1/2 hours later LHR-EDI (VS, operated by EI; "Little Red," right?), in late November. All one ticket, issued by UA.

Being a worrywart, here are my concerns:

1) In case of schedule changes or irrops messing up the connection, I assume that I'd be on my own to rebook, since the LHR-EDI leg isn't Star Alliance, even though it's all on a UA ticket. Correct?

2) If things go as planned at LHR, UA will have moved from T1 to the T2 by then. But I don't know when the VS domestic flights will make the T1 to T2 move. I realize a T1 to T2 transfer isn't the end of the world, but I wonder if I should make life simple and do the whole trip on BA. (I really prefer not to connect in the US instead; with my luck I'd be stuck in the snow at EWR.)

Sorry if these are stoopid questions. I'm not a road warrior like many of you. Any advice is greatly appreciated. Thanks!