Yeah, I dipped Witch for that exact reason (and to qualify for Spirit's Gift).
The one trick I kinda covered over is that Bandit the Riot Raccoon is actually combat effective starting at around 3rd level, thanks to the Halfling Shaman FC benefit letting you advance the Mauler Familiar Archetype a level quicker.
So the Raccoon is getting a +4 bonus to NA and has 19 Str. He can also stay in that upgraded form indefinitely, so you can use him as a mount or whatever.
I mean, Halfling Shamans are kinda silly anyway once you throw in Familiar Archetypes; by 6th level, their Familiar acts as if they were 9th level for NA, Intelligence, and special abilities.
By 20th level, we're looking at a Familiar equivalent to what a 30th level character would have. Despite the fact that 30th level characters aren't something Pathfinder lets you do, iirc.
For a normal Familiar, that's SR 35; sadly, Int and NA are just table entries, not formulas. However, the Mauler archetype explicitly states that the strength bonus is +1 at 3rd level, and +1 for every two levels after that.
That comes out to a +14 to Str. Which, especially if you start with a Familiar with decent Strength but Tiny size (like a Raccoon), means you are looking at a +24 to Str, which can pop right up to +26 if you picked the Mammoth spirit.
That's an untyped bonus, by the way.
Hmm... The Familiar Folio has a list of options anyone with a Bloodline can take which replaces their first-level benefit with a boost to their Familiar. I think you can technically grab those with the Eldritch Heritage feat (or a Sorcerer dip, if push comes to shove), so I'm going to give them a good look-through.
EDIT: Ooh, Witches have a couple options for boosting Familiars too, based off their Patron; doing so delays their Patron spells by a level, but if you're only dipping Witch to boost your Familiar...
I think the most abusable one has to be the one for the Animal Patron, surprisingly enough - it gives them the Speak With Animals Of Their Own Kind at 1st level, even if they wouldn't normally get it.
So phaedrus? That's how you stick the Protector Archetype on an Improved Familiar.