OK then do you have any ideas that would kind of stray away from the mainstream undeads ideas?
All I can think of off the top of my head is to put a cultural spin on it. You could make them seem more Egyptian or Southeast Asian, for instance. Also, you could make it so that not the entire faction was undead, but included some living units. One example I can think of is the Death faction in Lords of Magic. Although they do command a lot of undead, probably about half their units are living Dark Elves, as opposed to The Scourge in WC3 (or countless others), which is exclusively made up of undead.
Do you have a suggestion on unit name & position in the tech tree?
Southeast Asia: Crocodile, Giant Cobra, Tiger, Elephant (or stick with Mammoth), Necromancer/Reanimator/Priest of Death/etc
Egypt: Crocodile, Giant Cobra, Mummy, Scarab, Chariot, Necromancer/blahblahblah (with a big jackal headdress of course)
PS how is the tech tree? Too long or short?
It looks about the right size. Just try not to let your units' roles overlap.
Does this fit in Magitech in your opinion and if no, why not?
I think it could.