Well I do have to give it to you that EV1-1Ex having both Detector G and Detector AA in the same wave is kind of a bitch to deal with unless you nuke everything before they move. Later stages are probably easier than that.
So easy cheese No. 1: just use ID + Maria, it probably work for pretty much every maps this event since Anti-ID stuffs weren't added yet. Although I suppose this isn't really fair.
Easy cheese No.2: Just use EVA Khan. Everything is forced to target her, which she can all dodge. Just bring some DPS and you're pretty much set. Khan is farmable, and her equipment is in Monthly Exchange.
Still though, Get ID + Maria if possible, since it's faster.