DY: Once again, I don’t disagree. Chazal say that Levavchem & Aineichem are Minus & Zenus (also see Rashi in Yoma 29a on top (something I found researching this topic)). But Hirhur Halev (seemingly) applies to other items, and Lo Tasuru is only to fantasize about doing actual Issurim (which is what Rav Moshe explicitly states, as you quoted). The best you can do is prove that Lo Tasuru is Minus & Zenus, and I can’t prove that it is also specifically talking about other things as well, although those are (seemingly) also Assur to fantasize about (and proven via the Al Cheits).
The Gemorah (BB, I’ve quoted it before) says Gezel is even worse that Arayos, which may be why the ????? ????? adds Chemdas Mamon to the items that are examples of Hirhur Halev (although seemingly the list is not meant to be exhaustive).
I feel like we are going in circles.