Inkjet is fine, as long as you tell it to only print with black ink (and as long as you check closely with a magnifying glass afterwards to make sure it has done so).
You are absolutely right. I figure it would be best to do it at night, with a light shining in towards them from outside, giving them the rim light you want.
Ah, give them a chance, I guess.
Don't change your editing workflow, of course. Just convert your file to Adobe RGB when you're preparing the print file.
Alas, no, it's too clumsy. Much slicker to keep them as two separate actions, and have them set up as two F keys on your keyboard. Eg F2 to run the BW, then choose the layer/s, then F3 to save the PSD.