Those CV's are very efficient (97dB) so you don't need much power OR high current to make these play ear-bleeding loud. 100 wpc with these speakers should be more than enough. Either brand of amp will work just fine. However, since you don't need a ton of power you can go with a lower-powered less expensive amp and still get plenty of clean sound. I've never heard Emotiva, but I've been a long-time owner of Adcom, so between these two my vote is for Adcom. If the GFA-5500 is a good deal, go with that, but the 125 wpc GFA-5400 would be equally capable in this installation.
FYI, impedance for the CLS-215 is listed on the owner's manual as 8 ohms, so no need for a low-impedance capable amplifier. Also, the 500 watts max spec is the maximum instantaneous (i.e. millisecond burst) input power rating, not the continuous power rating.