The SLAI/RM family does not "talk" to other products from PreSonus, so you have to create your own solution. The most simple and effective solution would be to run 2-3 long XLR cables from stage to FOH. Use one cable for talkback and another one for headphones. It may be that you need a headphone amplifier at FOH, but that doesn't need to be special or expensive. You may also consider buying or making a stage snake / multicore with 4 or 6 or 8 channels, if there is more audio needed at FOH (delay lines, auxes/subgroups, CD player at FOH). Another alternative is audio over ethernet. One CAT5 cable can handle 4 XLR signals. This was invented for lights control, but you can also use it for audio. Two special adapters are needed; the cable does not need to be special, but of course it should be "road ready". And if you add a router (dual band), a short CAT5 cable and an iPad (second hand...), you will have (almost) perfect control at FOH. RTA is still missing on iPads.