Correlative clauses and anaphora

[faiuwle]

Let me see if I understand this right.

If you have a sentence with English-like word order and a standard relative clause that looks like this in gloss/diagram:

[[noun [that vbs obj]] vb2s obj2]
or
[sbj vb2s [noun [that vbs obj]]]

then the correlative sentence can look like any of these:

[which noun vbs obj] [that vb2s obj2]
[which vbs obj] [that noun vb2s obj2]
[which noun vbs obj] [that noun vb2s objs]
or
[which noun vbs obj] [subj vb2s that]
[which vbs obj] [subj vb2s that noun]
[which noun vbs obj] [subj vb2s that noun]

where "which" is a relative pronoun and "that" is some kind of (possibly correlative-specific) anaphor.

1. Does this kind of thing ever happen:
[which vbs obj] [that vb2s obj2]
[which vbs obj] [sbj vb2s that]

in particular, would this mean "anything that X also Y" or "there exists something that X which also Y"? Would it need some kind of dummy pronoun at least?

2. If multiple things in the sentence are modified by relative clauses, I guess the various pronouns would need to agree with each other in some way - or is there another way to mark it?

E.g. in "English"
[[noun [that vbs obj]] vb2s [noun [that vb3s obj2]]]

would be something like
[which-MKR noun vbs obj] [which-MKR2 noun vb3s obj2] [that-MKR vb2s that-MKR2]

Marking for case would seem like the obvious way to go (or classifiers/gender, or number maybe), but if the lang marks case only by word order would it also work to require a specific ordering for the relative clauses (like subject relative clause always comes first, or something) or does that not happen?

3. How would you do this:

"English"
[noun [that vbs [noun [that vb2s obj]]] vb3s obj2]

Something like:
[which noun vb2s obj] [which noun vbs that] [that vb3s obj2]

where you just assume that the "that" anaphor always refers to the "which" in the previous clause? I imagine this starts to get hairy for sentences like the ones in #2, though, if you have word-order-based "marking".

[faiuwle]

No one? Not even THC?