Now that I've had a little time to experiment with Infection and Contagion, the feedback I'd provide would be - normalise the out of ring timer to 30sec minimum to allow more mobility, or else increase the % chance of spawning a ring on the residuals, the game often has downtime between skirmishes room-to-room or wave-to-wave and if we are already expending 2 arcane slots it feels better not to feel pressured for time to upkeep them with rng kill chances.
For Infection, other than increasing the timer to 30sec, if a change were to be made make it so companions/summons who are buffed by In