So I am at the point in the game where I need to fill up my pokedex and find and catch Mesprit, Uxie, and the other Pokemon I forgoti the name of xD So I went to catch Mesprit first, and it disapeared and Rowan came up to me and asked me to go get the Mesprite tracker thing for the poketech. So I did, I have heard that Mesprits face is supposed to appear on the tracker so you can find it. Well mine didn't! I have read EVERYTHING and tried everything to try to get it to appear on the map. Now it could be ANYWHERE nad I really don't have to time to search every inch of the sinnoh region for Mesprit. Please help?
P.S., also I have been hearing about a Pokemon called Cresselia, WHAT'S THAT??? Do I need to ucatch that too?? There are only three lakes, so where and how can I catch it?