...if l leave the FWD fuse in, and just run it in front wheel drive indefinitely? Or do l need to remedy the binding issue right away?

Just to clarify: the binding went away completely after the FWD fuse was put in.

Many thanks!

Try driving in tight circles in one direction then the other direction in a parking lot. Sometimes you can loosen the clutches in the rear of the transmission (for the rear wheel drive portion of the transmission) without having to replace them - old subaru trick. Also, are all of your tires the same size / brand / tread depth? That could also cause binding. Try the driving in tight circles trick first. If it does not work have it inspected - binding usually means there is damage.

This will usually fix the problem. You've done the right thing by putting the FWD fuse in this tells u tha t the 4wd clutch contol solinoid is working. The next step is to warm up the transmission & completly flush the transmission.
To do this drain the transmission sump & refill it, them remove the trans cooler hoses at the radiator & put them into a large container to catch the oil (you may need to connect some long hoses to the pipes to do this. Then get more new oil, get someone to start the car & let it idle in neutral while u add new oil, this will pump the old oil from the convertor out of the trans & pick up the new oil u r adding, keep doing this untill clean oil is coming out of the cooler hose, turn off the engine then top up the trans to the correct level.
Dont let the trans run dry during this procedure or u will do damage!!
Reconnect the cooler lines to the radiator & check the trans oil level.
Take for a drive & do lots of tight circles then recheck the oil level.
Hopefully now all should be OK