the simple answer is yes.
can I send IR to FOH but not backline? Output menu- there is an option for “monitor cab off” just tick this and FOH will get the full signal chain but Monitor/speaker out will get it without the Cab block.
Can I make my own IR? Do you need a traditional Ir or are you referring to the Cab portion of the KPa profile? The answer to both is still yes. If an IR just make it as normal and import it in to Rig Manager then load into the Rig you want to use it with. If the Kemper Cab section. Make a Merged Profile. This includes both the full studio profile (including cab and mic) and a Direct Amp Profile. It then extracts the Cab section by subtracting the DAP from the Studio Profile to leave just the Cab portion. Monitor Cab Off works as you would expect even with your own profiles.