I don't think there are canonical stats for any of those characters.
In RMSS/RMFRP, you could do animal companions with mentalism or a totem familiar with channeling (Spirit Law). There are also talents and background options for that sort of thing (e.g. Special Familiar in Character Law). Most of those are not in the core, although "loyal domesticated creature" and "loyal unusual creature" are background options in the RMSR.
You can also get animals from training packages, e.g. Animal Friend (various), Cloistered Academic (pet), Guardian (an animal companion), Shaman Priest (small animal companion)... and those are just in RMSR. Missionary in the Channeling Companion can grant "traveling companion/familiar" and Witch has "true familiar". The Essence Companion has Animal Handler (lots), Arachnamancer (pet spiders). Mentalism Companion has Beast Master, I stopped looking at that point.
In terms of items, Familiar is a 1st level spell, and you only need to cast it 7 times. At RMFRP Treasure Law prices, you could get 7 one-shot items for 7x14=98gp, a Daily I item for 130gp (but that covers the entire party if you hand it around), a wand for 180gp, 7 potions for 7x24=168gp, or 7 runes for 7x16=112gp. And quite a few TPs can grant Daily I items.
So... lots of ways.