It worked!
I've received everything except for the combiner (backordered), so I detached the bowtie antenna and went ahead and setup the YA1713, added the FM trap, and connected to the tuner. The problem channel WLOS now appears with a strength of about 70 (on the TiVo scale of 100), up from 0 to 25. It's sensitive and I'm still tweaking the orientation, but I'm very happy so thanks for your guidance.
Interestingly (to me at least), this VHF antenna is also picking up UHF channel NBC WYFF 36. I did lose the Fox and CW UHF channels - hopefully all will be good when I can combine the VHF and bowtie antennas with the UVSJ.