Hi Jennifer,
Unfortunately this was not the case. None of my features overlap at all, yet the MapTips do no play well together. They never all (3 feature layers) honor the HideDelay. Usually either my polygon layer works and the two line features don't or vise versa, but never all three.
It think it has something to do with how they are initialized. My poygon layer is by selection, so it is tied to an editor, the line features are on demand, with scale dependency so each of the three layers are, by design, turning on and off quite frequently and hence, the delays are maybe not getting set? does that make sense?