So, it seems the Synthesist is causing a few hiccups when it comes to rule interpretation and I've tried to do as much research as I can on these questions but haven't found answers for all of them so I figured I'd post them all here at once.
1) Do I have to spend evolution points to gain weapon proficiencies that I already have as the summoner?
2) How does healing work for the eidolon's temp hp?
3) For granted feats (i.e. Multiattack), does the eidolon still get that?
4) If I'm, say, a halfling with 20 feet speed...would I use the 40 of a quadraped eidolon? And if I had a climb or fly speed, would I still be able to use it?
These are all questions asked by one of my players and I'd love a bit of input from some GMs more experienced than myself.
Now, for the question of healing the temporary HP, this is an answer I found somewhere else on the boards here and is probably what I'll stick with unless someone can come up with a better one:
"Actually, the way I read it, you gain the eidolon's hp as temporary hp. When these temporary hp are depleted, the eidolon is shunted back home. However, from my understanding, the eidolon doesn't actually take damage. It can't be targeted separately, so it can't be turned to stone, or take damage in any way. Next time you summon it, it should still be at full health.
I guess that's how you replenish your temporary hp. Resummoning. Is that too strong?"