Triggered evasion is a really difficult thing because you need a full damage detection system for it. It's possible that evasion abilities stack multiplicatively (dodgetotal = 1 - (1-dodge1)*(1-dodge2) instead of dodgetotal = dodge1+dodge2, which would be additive stacking) in which case you're in luck.
The reason it might possibly be multiplicative is evasion has a 100% hard cap, and capped stats don't play nice with additive scaling. To test, make 2 separate evasion abilities that each give 50% dodge. Put one on a unit and confirm that roughly 5/10 attacks miss. Then add the second ability and see if you get any misses-- if you do it's multiplicative (50%+50% should be 100% dodge). If about 5 still hit then the abilities don't stack at all and you should retry with one ability based off Drunken Brawler and one off Evasion.