Hi there, I just watched this video: Learn 4.3 - Diminutives for Tiny, Cute, or Baby Things in which she explains that -IT- should be used for words that end in a, o or consonants other than n or r, whereas -CIT(o/a(s)) is for words that end in n, r, á, ó, e, é, i, í, u or ú. The two seem to complete one another, but we know there exist more -forms- than that.
At 7:32, she mentions the less-used diminutive '-ill(o/a(s))' and in the part after that, she goes on to list '-ico/a(s)', -ín & -ina (which I assume is simply the feminine version of ín). She doesn't give rules on when to use these or any examples. (apart from a few words that evolved from another + ill: manteca->mantequilla, mano->manecilla, bolso->bolsillo.. looking at maneCillA, I'd say there are still some secrets to be revealed..)
I'd love to know how exactly to use them, and if there are more. Could someone elaborate, please?