I plan to install 3/4 X 3 1/4 Brazilian Cherry over a 45-year-old 3/4 subfloor.

Unfortunately, I have to first remove a layer of glued-down 1/4" oak parquet, resulting in some damage to the sub-floor, such as tearing spots of the top ply of the plywood, in some cases a foot square or so.

In one area, the addition of a new 1/4" underlayment over the damaged floor will smooth things out, but also improve some height problems. However, in the bulk of the space, height is a an issue.

Is it possible to lay the new floor directly over the old parquet? I'd like to screw down some squeaks first.

Best advice for installing an underlayment?

Not advisable

I didn't think so. Therefore, my plan is to remove the parquet (not easy, but at least it is only 500 sq. ft)

Best advice to deal with the expected damage? De-lamination from tearing off the top ply of plywood in some areas.

Underlayment? Sand & fill? (with what). Or, just build up with some 30lb felt, cut to the shape of the tear?

Thanks.