[Bob Andersen]

I'm currently restoring a Philco 15DX which uses the same chassis over in this thread.
My chassis is pretty much stock so you can compare the photos to your set.
As for your questions...

Yes, it used Mershon caps. Mine had been replaced with cheap cardboard Aeorvox caps.

Yes, that's a replacement power transformer. The original part# is 6672

I'd need a better photo to say for sure, but from what I can see the audio output transformer is original. So is the filter choke next to the power transformer.

There are no paper caps in this set. Only the bakelite blocks and metal box caps.

Good luck! I hope to try firing mine up next week