OK we'll call that a draw on the silly mistakes ! 
Thanks for the explanations.
I'm not sure of the developers' position on this, but my experience is that the fpc wrapper is backward-compatible (i.e. works reliably with versions of ppc* significantly older than itself) and that it's fairly happy if ppcx64 etc. is symlinked to e.g. ppcx64-3.2.2 which is itself symlinked to /usr/local/lib/fpc/3.2.2/ppcx64. This is also compatible with the fpc -V option, although whether that works reliably is patchy.
Apart from fpc, fp and fpcres all the binaries that would normally have gone into /usr/local/bin are actually in e.g. /usr/local/bin/fpc.d/3.2.2
Both the above are with the caveat that I adopted that convention a significant number of years ago, and more recent "official" alternatives might be more reliable.
MarkMLl