1. Yes.
2. Not really.

1. Since there is no cowl or cheeks in front of the firewall, almost anything will fit. The 65LA only weighs an ounce or so more than a ball bearing 46 so it should be fairly easy to get the CG right by moving the battery pack around.

2. I think the plane comes with an aluminum engine mount that is not adjustable for width. You might have to replace the mount, which will probably mean drilling holes and installing blind nuts for the new mount. This is not hard to do but it does take some time and patience. I tend to favor an adjustable mount like this one, others dislike them:
http://www3.omnimodels.com/cgi-bin/w...I=GPMG1061&P=0