Let it dry out thoroughly, I had the same problem and mine came back after neglecting them, as in letting them go dormant and dry out (out of the sun, dark barn) for about four weeks. I then took them out, put them in clean soil and they all greened out again. I probably won't get flowers for a very very long time but I know they are alive :) You'll just have to ignore it and pretend it doesn't exist LOL

Protect it from rats, mice, and other bugs while this dormant period goes on.

Could I clone/cut them once they are thoroughly dry, or should they have roots before I do that?

I stuck it upstairs in the attic (real hot and dry), and will let it sit up there until September.

I think as better to cut rotted roots, then soak in a solution of benomyl bulbs for 30 minutes. Bulbs dry for 2-3 days, and plant them in an almost dry, with good drainage and soil. Plant so that the bulb was almost on the surface of the soil. Sprinkle the bottom of the bulbs under the vermiculite. Carefully watered a little bit when the soil is completely dry. No need to arrange their rest period, they now have to grow on.grow new roots. And for the rest period is too warm.
:)

I agree the "real hot" attic is not good. If need be put them in a drawer inside the house. No do not cut and clone at this point, you'll kill it off completely.

As for the "no rest period" I'll let you all decide that.. I just told you my opinion and experience, believe me I have had a lot of bad experiences, I'll leave that up to the real experts

Excuse me, what is at stake: the hippeastrum or about Amaryllis belladonna?

huh, maybe you misunderstood me, I am still learning so keeping the beautiful beast alive is most important to me, thus my statement "I probably won't get flowers for a very very long time but I know they are alive :)" was overlooked