"I had the exact issue. Turned out to be a power problem.
I my case, my USB port couldn't power the APM and my rx at the same time. I had to connect the APM by itself, no rx, no telemetry radio if the USB port was the supply.
"You are probably better off with a MAX7456 as it is designed for graphics. The IC used in the Video Experimenter (a sync separator )is not designed for graphics. You can find an easy to use one here: https://www.sparkfun.com/products/9168"
"Instead of using the through holes, you could spit the wire so that half of the strands are one 1 side and half are on the other. Then use heatshrink to cover everything. The hot glue will probably come off eventually. Similar to what I did here,…"
"I guess you'll have to prove that the BT module works and is working at that speed. Use a phone with BT and try to send data to a PC using the FTDI cable. Ensure everything is set to 57k and see if the data is readable or gibberish.