I'm nearly code-clueless, so it took me a week to muster the courage to follow your instructions. In the meantime, I continued hunting and testing some less-scarey-sounding solutions—nothing else even comes close to What I Want to DO and Looking How I Want it to Look.
Then I found the cPanel Code Editor with numbered lines that correspond to the ones you cited. So I held my breath and DID it...
BINGO—it magically works like a charm on the first attempt! Now my lovely theme-customized search widget finds matches in pages AND in forum topics [this site has no "posts"].
Thank you SO much for your above-and-beyond theme research and personal attention,
P.S. Maybe in the next update you could extend the search range to tablepress text too? Funny, the widget I used before DID find tablepress entries [attached to WP pages because they aren't supported by bbpress]. This feature is not so important for my forums site because most [eventually all] lines in the tables link to topics. Even so, it may be super-important for someone else.
P.P.S. Another idea... The default Suffusion search widget offers the option to highlight "hits." This is a nice extra even tho browser "find" features have the added muscle to navigate back-and-forth among them.