I've found the answer to Q3:
http://www.pelicanparts.com/cgi-bin/vb/showthread.php?s=&threadid=56945&highlight=fuel+filter
For Q2, short of installing a factory air cleaner system, I am going to wrap my K&N filters with an open-cell foam precleaner or this new K & N wrap -
http://www.knfilters.com/wraps.htm
Also, I dissected my old fuel filter and nothing unusual was found, so maybe a rusty tank is not my problem.