I solo-ed Meli on my tamer a few times but honestly I wouldn't recommend it: It's boring, since pretty much all you do is cast heal on your pet, and it takes
forever. I used a Cu when I did it, maybe with one of those Greater Dragons it's more feasable. I didn't get a chance to try that yet.
As for a template, I used a very much tricked-out mage/tamer/arcanist. So high magery, eval, resist, spellweaving, taming and lore, no vet. Avarage Medi, very low necro (enough to cast lich form with items) and ofcourse loads of MR items.
You really need all the mana you can get course you have to be able to sustain pretty much constantly healing your pets. Having said that; All my attempts were
before the latest mana changes. I'm not at all sure it's still possible to regenerate enough mana to sustain such an effort.
Good luck if/when you decide to try