Successful repair of my 3325B function generator rear panel output tonight. I swapped out the existing A22 board for another the fellow I purchased the instrument from sent me, and just like that, the rear panel output is fixed. I decided not to try desoldering because the particular transistor that is bad (circled in the pic below) is basically unobtainium and I only have the one replacement currently. So the old A22 board will be saved as a parts mule, if the need ever arises. The A22 board is kind of weird. The majority of it is the power supply for the whole instrument, with +5, -15, and +15 Vdc rails, while the small strip drives the rear panel signal and fast sync outputs.
The 0-60 MHz fast sync works now too. Not going to use the rear signal output that much...I bought this unit for work in audio frequencies mainly so the 0-20 MHz output on the front panel is completely adequate. Curiously, the "0 dBm" rear signal is really 10 dBm...either way it is unfortunately fixed amplitude so perhaps less useful.
Bonus pictures of the frequency domain view of a 10 MHz square wave from the 3325B. Shows why you need a significantly faster 'scope to get a clean view of the waveform than for a pure sine of the same fundamental.
FWIW, the 8568B RF unit I'm using was a factory 8568A -> B conversion, so that's why the 8568B is tacked on.