Is it still gonna get Blood Lust eventually? If not then I don't see it on the plus side since Blood Lust helps a lot more than SBR, unless you get an Eira, though you'd still probably rarely use it anyway.
Yes it will get bloodlust normally.
well the homunc is already gimped since it was evolved prepatch. not sure if it's worth feeding up just to get the skill if you plan on remaking.
Depends if you decide to remake. IT's only that SP/HP, not your six stats (those will hit cap as homun S). That said, SBR is not a very useful skill, and doesn't synergize at all with the other skills you've gotten.