yeah, i think the vocals stuff is generally among the least problematic regarding A.I. use. just my 2 c.
btw...i didn't even think of the obvious in my last post... a screenshot of the arrangement window of your sequencer is pretty decent proof that you atleast put some level of work into your remix. it doesn't say anything about where the MIDI data came from, of course. that could always be (partly) A.I. generated.
but if a mix from a newcomer seems sus, asking for a screenshot of the project would be one means of clarification...atleast somewhat.