Joel, lots of excellent information you have there.
However, I think you have one mistake in your "Version Compatibility
Matrix". You list AOLserver 3.5.5 as "Verified" for OpenaCS
4.6.2 and 4.6.3, but AFAIK no stock AOLserver 3.5.x version
include the ArsDigita-derived character set support required by
OpenACS 4.x
I remember when the character support was discussed on the AOLserver
list and on openacs.org, and AOLserver team's decision was to skip the
work necessary to add it into any AOLserver 3.5.x point release, and
instead to put it into 4.0 (which they did). So unless somebody
changed their mind about that, I don't see how AOLserver 3.5.5 could
be fully "verified" for use with OpenACS 4.6.x. There might be a
patched version of 3.5.x around somewhere that has the necessary
character set support, though.