I would highly recommend against that the coil conversion. Especially because you tow.
The compressor can be rebuilt. https://www.amazon.com/Suspension-Compressor-Cylinder-Repair-VUB504700/dp/B07XLKV8N2/ref=psdc_15731661_t2_B075SLHM8Y
Dont forget a drier and seal kit also.
I find it odd that both rear bags need replaced. But it can happen. I'd bet on a valve block needing rebuilt.