For skills, all you really need is 20 skeleton mastery, 20 skeleton, and 20 corpse explosion (CE does a LOT of damage at high levels, and it has a long range), but I'd recommend 20 into skele mages as well after those (to help with physical immunes, though you can kill PIs with corpse explosioin as well). I'd also recommend 1 into summon resist, revive, amp, decrepify (the slowing sure is nice on extra fast fanta specials). I'd put any remaining points into bone armor.
Max block isn't necessary...just be cautious and stay behind your minions and you should be fine. Max block will require quite a bit of dex, even if you use stormshield...and those points are better spent in vitality imo.
Yes, I'd use the act 2 might merc.
Here are the changes I would recommend to your gear:
Beast
Natures Peace (oak, and I can revive the monsters infront of pindle)<-seems like ok choice, but Bul-Kathos or a rare ring with strength, life, and res would be better
Fcr ring <-personally I dont think fcr is very important for a summoner, but if you can find a good fcr ring (strength, life, res) this is ok
Arachnids <-for hardcore, it would probably be better to wear dungos (life, replenish life, damage reduction) or tgods (adds a lot of strength, light sorb helps a lot on souls...you should at least keep it in stash)
Trang Gloves <-good choice
Marrow Walks <-good choice
Hopefully I get a 3summon 10fcr amulet..or crafted 8fcr to hit 48fcr bp <-switch this to maras or rare/crafted with skills, life, res, str
CTA + spirit<-yep, of course
Shield <-spirit monarch (the fcr should allow you to swap out arachs and the ammy and still make the 48 fcr bp)
Armor<-use Enigma unless you want to play safely and not telport at all...if you're gonna walk a lot use CoH
Helm<-Shako-Life, +All Skills, and damage reduction
Gear for my merc:
Vamp Gaze <-good choice
Bramble <can 3 auras be activated on my merc?> <-good choice, if you want to increase his survivability use shaftstop or levi
Pride <-good choice, if you want to increase his survivability use reaper's toll (massive life leech)