...it takes about 25seconds to get up to enough voltage to hear audio.
Take a close look at the squidmatic for a condenser across the AVC line intended to dampen the response time. There's usually something to reduce the chances of volume overshoot / pumping / or blasting on a station or mode change, and a leaky condenser can take a while to charge. Failing that, look for a resistor intended to pull up, pull down, or bias the AVC voltage that doesn't do that trick like it used to. The AVC line is a simple circuit if you can see the trees through the forest.
I removed the speaker leads from the radio and I still can hear audio coming from T6.
Very common with any audio amplifier that uses a transformer for interstage or output coupling. Also not unusual for the grid of an output tube to talk to you if you listen closely...........