A132: It's Diminutive, so it can share your size. (Anything that's Tiny or smaller can freely do so, as otherwise they'd not be able to attack with 0' of natural reach.) Actually granting it total cover is not hard either so long as you have an appropriate container for it - total cover depends on some obstacle blocking line of effect. My preference goes to the Familiar Pocket (Sor/Wiz 1, SC) spell - it lasts an hour per CL, and can store more than just familiars despite the name.
A133: Given the wording, I'd assume the former. (Keep in mind that Sainthood carries significant roleplay requirements.)
Q135: In an earlier thread, I'd asked about feats and other effects that can swap around primary casting ability scores. I'd been pointed to Academic Priest and Dynamic Priest, which swap divine primaries from Wisdom to Intelligence and Charisma (respectively). Is there any similar feat or so forth that would swap an arcane primary casting ability score?