That’s exactly how I’m doing it now. Or when a “class” has some activation perks per level and some functions to check if the multiplayer cheater is not trying to exploit it - I spawn an OBJECT without tick enabled and just call interface on it. I was just wondering if I can make a custom ability class that is an object that is a bit more stripped down. But to think of… that’s a lot of work to make it happen in comparison to just having replicated objects that are custom and took me maybe 1h to setup.
Oh and cost of ability is 0.1ms inclusive max when it runs all the “can activate” can cancel" etc triggers on the single frame… usually running a ticking passive is 0.01ms 
so having over 700+ starts to be a problem. And I got a slow CPU (3.2GHz max turbo, and 2.5 GHz typical clock speed)