1. Fay Crozier Augments > Soul Scourge > Pet Attack Magian, I don't know of a better stave for just physical bp that's out atm. Checking the magian staves I can't see much else there's the acc version you may want to consider if you try to use multi hit bps on higher end mobs, generally you benefit more from accuracy than attack for multihits because hits often miss due to how how much less a difference in what pets can stack vs what players can.
3. Gifted Earring for set bonus proc from caller's, Summoning earring, Augmented Pet attack earrings from mini story lines(don't know which), etc. are some good options.
Gifted earring is probably best inslot to use with the Esper Earring.
1. I think you have that backwards. Should be Fay Crozier < Soul Scourge < Magian. I believe that's what you meant but had greater than instead of less than.
Outside of Nirvana Aftermath, you're correct as that's pretty much all there is.
3. +Bloodboon does not effect the proc rate on SMN empyrean. Likewise, +Triple Attack does not effect THF, etc. It remains a flat rate. While you will proc blood boon more with gear, you will still only proc the augmented blood boon X percent of the time (depending on gear). BG wiki lists a source on the caller's attire +2 page.
And to the OP:
2. Usually those land no problem but there are a few enemies that can evade them a bit (particularly annoying for shock squall, e.g. Diabolos Mega Boss in Dynamis evades it often). I would say if you get into content where they aren't landing (and your skill is capped) consistently, consider making one. If not, I wouldn't worry about it.