None of those C or C++ compilers came from Bell Labs, or were on UNIX tapes from Bell Labs. I used Cfront on Apollo machines in the '80s. Effectively nobody was using Cfront by 1992.
Apple, particularly, was not strongly influenced by Bell Labs or UNIX. Apple A/UX–a UNIX for Macintosh, a niche product from that period–shipped without a C++ compiler. MPW in 1992 shipped without a C++ compiler.