Well I managed to get them to taste it, one as a TEC Loyalist, the other as the Rebel.
I had currently been running flagship victory to prevent absurdly long games, however I'm beginning to think that's a bad habit. A second free cap at start feels a bit like cheating to me, yet endgame it doesn't last nearly long enough.
I will test Diplomacy/Research victories to see how those behave. Also while I stated they are competitive, I offered them online human battles and they both decided they wanted ez-mode learning with training wheels first. I wanted them to get used to the keybinds, map movement, map awareness, and most importantly research / planet development.
Once they get the hang of it I'll start making them fight people.