Can samples in Allprotect Tissue Reagent undergo repeated freeze-thaws without degradation of DNA, RNA, and protein?

In general, yes. Freezing and thawing a sample incubated in Allprotect Tissue Reagent several times does not affect analysis of RNA and protein in downstream applications.

However, if you would like to perform protein activity assays, you should test each specific assay, since several freeze–thaw cycles might reduce protein activity, depending on the protein being assayed.