need acoustic effects

Would simply adding an ABY pedal as the first thing in your signal chain after the guitar serve your need? Just put the pedal in Y mode,and send you guitar signal down to separate paths. Maybe I missed something, but where does Reaper come into the equation?

Bursting to make a comment about them forgetting, but.... I will be good. There are a ton of pedals like that out there, most of which allow even more flexibility than you need. I asked my friend John who is a really good performing acoustic guitar player what he has. L.R> Baggs venue pedal. Not cheap but very versatile and impressive. Fishman also do a good one.

Any decent DI with a thru jack will do what you want. Plug into the instrument input on the front. The parallel or thru output goes to your pedal board and into one channel on the PA and the XLR balanced out goes to another channel on the PA via mic cable. You can blend them either at the PA (if you have a sound guy) or using a volume pedal as the first effect in your pedal chain Check out the very common Radial JDI for instance