Probably, it would be helpful to know why one would like to analyse fragments of phrases. Fragments are not utterances, they don't have a truth value, they only appear as parts of bigger phrases and their grammaticality can not be judged. Furthermore fragments are highly ambiguous. "und auf die" e.g. could be a part of "Er wartet auf Maria ["und auf die" Kinder"], or "Er trinkt wieder ["und auf die" Kinder hat er wieder nicht aufgepasst]." In these 2 structures, what is coordinated are completely different things (PPs or CPs). It is the complete structure which reveals the function and the combinatorial potential of its parts.

Coindexation of "he" with "cousin" in (7a) and "she" with "cousin" in (7b) could make it more clear that it is not an interpretation like (6b) which is intended. The same conindexation could be used in (6) to make the marking consistent.

italics for emphasis? since you have talk very much about sexus.

To make the point of syncretism (and not of "portmanteau morphemes") clear, it would be better to give the example pairs that coincide "as (43a) and (43d) and (43c) and (43e) show".

italics for emphasis

italics for emphasis

Singular

The number of the example would be helpful

Italics would help to understand that "optimal" is used here as an example.

adjectives have positive, comparative and superlative wordforms

It would be good to make this point clearer with an example.