One way to get the reverb in time would be to bounce it to a new audio region. then move it into time with the percussion.
Make sure you get the right reverb sound first, because you can't tweak the settings once its a bounced audio file.
As for the phase issues, i'm not too sure - without hearing the reverb it's hard to tell.
Is the reverb on a different channel fro the guitar - set up as a send? or is it on the same channel strip as the guitar? Have you got any effects on the original guitar track that affect phase? If these are going to the reverb then they may be contributing to the phase issues.
Try taking off any other effects that might affect the phase, and send a clean signal to the reverb.
Or you could also try:
a)changing the order of the plugins
b) putting a stereo gain plugin on th reverb track and swap the phase around until it sounds better
c) experiment with different reverb settings
Hope that helps for now