So did I understand that right that allomorphs include:

zero morphs (and suppletion?), Umlaut and the regular s (cats, kisses...)[Image]

Question

So did I understand that right that allomorphs include:

zero morphs (and suppletion?), Umlaut and the regular s (cats, kisses...)[Image]

Answer

yes, this is correct when talking about English nouns. 
Suppletion is common in the pronominal system (I / me, we / us etc.) or verbs like go/went.
When talking about verbs, ablaut is also a common phenomenon (sing/sang/sung etc.)