How much oil is leaking and where does it collect/end up? Front, rear, left or right side of the engine? Taking a picture & posting it here would be helpful. Otherwise we would just be taking wild ass guesses on the source of the leak.
Not sure why you would just go ahead and replace an oil pan gasket for a leak you described as "serious". "Serious" means lots of oil volume/flow to me. An oil pan gasket leak would never be a gushing or "serious" leak as you described. Did you try using normal automotive troubleshooting techniques to spot the leak before diving in to replace the gasket? I.e., clean the oily mess with engine cleaner/water WITHOUT taking anything apart, run the engine, observe closely and ID the source of the leak.
The plastic lines you broke were the oil metering pump feed lines, so you just created a new oil leak you need to fix. There are 4 plastic lines that run from the metering oil pump (MOP) on the engine's front cover, to the 4 oil injectors on the block.
Since it sounds like you're a newbie on rotaries, and perhaps limited mechanical experience in general, the first thing you need to do is download an FSM (Factory Shop Manual). If you do a search for FSM this website, you'll find links to another website that has pretty much all the RX7 FSMs available for download as PDF files. Download the FSM for your car, and get very familiar with it.
Another great web resource is here:
http://fc3spro.com/TECH/PROBLEMS/P1/...IL/leakso.html
That particular page talks to likely oil leak sources on the FC.