I think you have #2 and #3 backward. ISM is unlicensed and can't cause interferences to ANY licensed radio services, that's including amateur radio users.
I checked the regs, and looks like they may be effectively on the same level.
47 CFR 97.301 says that the sharing requirements for hams in 2.390-2.450 GHz are given by 97.303(d), (e), and (p).
97.303(e) says: "Amateur stations receiving in the 33 cm band, the 2400-2450 MHz segment, the 5.725-5.875 GHz segment, the 1.2 cm band, the 2.5 mm band, or the 244-246 GHz segment must accept interference from industrial, scientific, and medical (ISM) equipment".
So, hams must accept interference from ISM in that band, which would put hams equal or below ISM on my list...BUT I cannot find anything that says hams must not interfere with ISM, which would indicate hams should be equal or above ISM.
The one thing about ISM is that a lot of those are actually transmitting only; for instance, microwave oven. The fact that amateur radio service needs accept interference from ISM equipments just indicates the fact that hams can't report instances of interferences to FCC (as long as such devices are operating under proper conditions as described under Part 18) and unlicensed services usually receive very little protection, if at all, from interferences caused by licensed services.
47 CFR 97.301 says that the sharing requirements for hams in 2.390-2.450 GHz are given by 97.303(d), (e), and (p).
97.303(e) says: "Amateur stations receiving in the 33 cm band, the 2400-2450 MHz segment, the 5.725-5.875 GHz segment, the 1.2 cm band, the 2.5 mm band, or the 244-246 GHz segment must accept interference from industrial, scientific, and medical (ISM) equipment".
So, hams must accept interference from ISM in that band, which would put hams equal or below ISM on my list...BUT I cannot find anything that says hams must not interfere with ISM, which would indicate hams should be equal or above ISM.