RE: Trex V2 eccpm frames....which one???
I haven't had a chance to see any of the optional chassis you mentioned, so I can't say for sure what will fit.
but those 3107 servo's definitely won't fit in the stock Align CCPM servo mounts if you decide to go with the XL airframe.
You'll need the 3103's or something VERY close to it in size.
Good luck!
M