Pretty sure the Rogue is my "spirit animal", so to speak, regardless of game system. In my last few games I have tried to move away from that style (sneaky/sly/subtle, not the backstabbing/stealing from the party schtick), but each character did sort of migrate back that direction.
2 feats will get an animal companion at level-3, with a third investment getting it fully leveled.
Variant Multiclassing (VMC) into Druid would cost every 2nd feat (3rd, 7th, 11th), and would also provide a fully leveled companion (along with Wild Empathy and the Druidic Code).
Gaining a domain (via VMC Cleric or otherwise) and taking the Animal Domain will get them one at level-3, which again could be increased by Boon Companion.
There are at least a few more ways to get more restricted animal companions like those of Rangers or Cavaliers, but the above hopefully helps.
3 attempts so far, zero successes. Will most likely keep on trying.
Made it to Book 4 of Wrath of the Righteous. GM was moving out of state, and the group fell apart about 4 months pre-emptively.
I GM'd to the end of Book 2 of Giantslayer, life intervened with a player couple and we haven't met back up since.
Ran a single session of Kingmaker as GM for my long-time gaming crew (who were basically new to PF, but not 3.x), no player drive to have a second session. Oh well, only way to many hours of prep work for that one, ha.
Gunner Squire (Gunslinger)
I'm sure there are a few others that can be molded to fit your specific theme, but the above are all magic-free (until 4th lvl for the Pally). Hopefully you can retrain some levels once you feel the character has grown into a true adventure/hero.
GMs, have you ever let a new player to an established game, or a player whose character died, play a former NPC as their PC?
When in Book 3 of WotR, I was able to play a NPC the party had saved way back in Book 1 (adding class levels and filling out her background). I don't believe any of the other players realized who she was, unfortunately. Considering most of the original PCs that were around in Book 1 had died or left the party by that point, maybe it was simply appropriate role-playing.