Given the timing, I doubt it. Apple has established a fairly stable cadence of core improvements every 12 months. Enough time has elapsed between the M1 and this new chip that I'd expect it to have more in common with the "Apple A15" generation SOC than the A14/M1.

As to what Apple's choice of marketing name, that's entirely arbitrary. (For what it's worth, my guess is they're ditching "X" suffixes and will designate higher spec variants with other prefix letters e.g. the "P1" chip.)

Considering M1 doesn't support LPDDR5, and A15 will be in a similar time frame. I would not be surprised it will be a M2 ( Based on A15 ), or more likely a M2X.

I'm not sure about that, because the M1 cores are, in essence, quite old at this point; they're pretty similar to the A12 cores. Apple usually does quite a major micro arch refresh every few years; it's probably coming up to time.