EL84 is nine pin, so no go. Unless you get some Yellow Jacket converters.
Pre amps are basically V1 is closest to the input jack. The PI is closest to the power tubes. Just have fun swapping those around.
Bias terms are funny. Fixed bias means you actually have to adjust the bias. Cathode bias is where you just plug and play. The Tweaker is plug and play and you can use 6l6's and EL34's and probably some other octal based tubes like a KT77.
The manual should have pre amp tube stuff. Check...
Nick Pierro also does the X mod. RockStarNick is his user name. He does great work.
I'd be willing to send you the xman to try out and see if you dig it. Send it back if not happy or work something out.
Let me know.
I had an Eggie dual deluxe module for sale for a week with no bites on this board. For less than $300 too. Finally sold it on Rig Talk. Not sure why it didn't go quicker. It's a great module.