Yes, I think a bridge to NNTP would also be helpful. The ability to post through NNTP might be good too.
This would provide some of the listed features when using a suitable NNTP client; my own NNTP client called "bystand" supports SQL (it stores all data in a SQLite database; if you use the SQLite FTS extension then full text search is available), but other clients may have different features, so may be more suitable for your use possibly.
(I think that all web forums and mailing lists should be NNTP instead. It is OK to have a web interface too as long as the NNTP server and message ID can be read from the web interface (even if JavaScript and CSS is disabled), so that if you are given links to the web interface then you can access the NNTP if you want to do. It would also be possible to provide a email interface too if wanted.)
This would provide some of the listed features when using a suitable NNTP client; my own NNTP client called "bystand" supports SQL (it stores all data in a SQLite database; if you use the SQLite FTS extension then full text search is available), but other clients may have different features, so may be more suitable for your use possibly.
(I think that all web forums and mailing lists should be NNTP instead. It is OK to have a web interface too as long as the NNTP server and message ID can be read from the web interface (even if JavaScript and CSS is disabled), so that if you are given links to the web interface then you can access the NNTP if you want to do. It would also be possible to provide a email interface too if wanted.)