.
The phenomenon is called secondary recategorization. Here, it occurs when the non-count noun takes on a meaning of variety, example, etc. However, it is not a usual phenomenon-- it occurs primarily when the writer is envisioning several sorts of 'wine' or whatever. I don't think there is any rule to rely on, and I don't think a list of amenable nouns could be constructed. In the cases you present, these seem good to me:
When I got back home, I took
a short nap to make up for the previous night. --
Nap is countable here anyway. At the party, I met Sarah -- a woman of unusual beauty. -- only 2 kinds of beauty implied-- 'usual' and 'unusual'-- so not a lot of varieties envisioned
Well, at least we had decent accommodations. -- Normally a plural noun, which circumvents the problem.
It is alleged we have false information on the fugitive.-- Again, only 'true' or 'false' is available, but I think that 'information' strongly resists countability anyway-- I don't know why.
I had a good sleep before I set out.-- 'I had a sleep' is the collocation; the word is already countable. It also appears as a noncount: I had some sleep.
When he was in Rome, he developed (a) deep distrust of people. -- Both seem fine to me
You guys have
(a) better knowledge of the English grammar, so I guess you can help me. --
Both seem fine to me.Others may have other opinions.