Exlakewooder: I’ll repeat what I said, but I’ll break it down and be clearer because I don’t think I said it over properly last time. At least, I could have made it easier to understand.
1) Correct. There is a Machlokes between the Rambam and Tosfos as to whether or not a Niddah is included in that category. Tosfos says no. The Rambam says yes. We Pasken like the Rambam. There is no distinction whatsoever between someone whose wife is a Niddah and someone who is with an unmarried Niddah in this regard.
2) Touching is not a Harchaka. Harchakos are not handing her/passing her things, not sharing a plate, etc. According to all Rishonim (except for one opinion quoted but not ultimately accepted by the Ramban), Negiyah with any Ervah, be it your wife who is a Niddah or any other married woman-with the exception of one’s mother (and somehow the Minhag is to be Meikil by sisters V’tzarich Iyun Bazeh)-is it’s own separate Lav. Thus, since it’s a Lav which is part of the Issur Arayos, we Pasken that it’s Yeihareg V’al Ya’avor. Thus, this is not a Harchakah, but a real Issur that applies to all Arayos. So, whether this Issur applies to one’s wife while she is a Niddah (or to any unmarried Niddah), once again goes back to our Machlokes between the Rambam and Tosfos. We Pasken like the Rambam.