Don’t think you’d have any issue mixing fluxes, I used to pop a bit of sif flux powder in with my LFB to make it pink so that I could tell which brush I had used in it and which in the silver/stainless flux.
I also dip my 101 rod in boric acid powder once it’s hot, I think it keeps things cleaner. Flux coated rod might be good for that but I wouldn’t only use the flux on the rod.
Don’t think you’d have any issue mixing fluxes, I used to pop a bit of sif flux powder in with my LFB to make it pink so that I could tell which brush I had used in it and which in the silver/stainless flux.
I also dip my 101 rod in boric acid powder once it’s hot, I think it keeps things cleaner. Flux coated rod might be good for that but I wouldn’t only use the flux on the rod.