My suggestions would be:

• Fire Wolf: HoloWolz
• Grass Raccoon: HoloRacz
• Water Whale: HoloWhalz
• Electric Rabbit: HoloRabz

I noticed most of the suggestions are about word plays and substituting similar words, e.g. aqua for water, etc. Not saying that this is bad, but I just wanted to offer something different to the table in this brainstorming session. :)

So I thought of suggesting names where HoloZing is featured. One, because HoloZing is the name of the game and these are the first starters of this game. Two, this would give some unique-ness to the names or it might just sound like any other Pokemon naming nomenclature, if you get what I mean.

Have shared more thoughts in this post: https://peakd.com/hive-131131/@relf87/how-would-i-name-the-holozing-starters

Cheers!