Yup, you got the right idea with the "skill" example. Really, for action sequences (and responses) your clip's "tag" can be just about any word, though there are some keywords you should avoid ("user", "target", and "none" - and while you can use the other keywords (like "hurt" and "battlevictory") in action sequences, they'll also be used for those tags' normal purposes and thus should be set with caution.)
For the record, if I had to guess what was going on with Victory UI, I'd guess there's a function we're both modifying in conflicting ways. My plugins try to avoid this when possible, but sometimes it isn't. That, or she's completely bypassing the usual "end of battle" functions, which my plugin relies on for the "battlevictory" and "battleend" tags. But without buying her plugin myself I can't look into the specifics.