Well first make a copy of the Default UI. copy that to a new folder (I put mine in the UI Builder folder.
Then using UI Builder open eq2ui.xml This will be all of your windows.
For the majority of your question look through the page GameData at the top of the page tree in UI builder. There you will find a bunch of data that you can pull.
for your exp the whole number would be /GameData.Self.ExperienceCurrent and the decimil would be /GameData.Self.ExperienceBubble
Look at the custom mods on this site that already do part of what you want to get all the details on how to do things (taking apart someone eles's mod is the BEST way to learn how they did things and how you can too).
for the Health/Power look at /GameData.Group.Group_1 and so on, got current/max health and power in there as well.
Best of luck, the forums are full of info and again, other people's work is the Best way to learn.
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