1-This really is just a design thing. it would take considerable amount of extra code (slowing down) the software to make the indicators update again after a button is drawn over it. That or it would make it a lot slower just redrawing all indicators regardless of them being updated or not.
2/3-The idea of clickable indicators was mainly for touch-screen users. If you use a keyboard, you can easily associate as many buttons to functions (globally or on a per-screen basis) as you'd like to.
4-I have plans of expanding the TAG support using winamp to allow improved tag support of different formats.
5-The font size is actually NOT resized, that's why you see them in the "wrong" position. This was done because resizing the font was not really looking that great, specially when most people were just resizing the skins for adjusting monitor position. The Y position is indeed being calculated, the code to resize the Height of the font is commented out.
Any help you or anybody else can provide, with docs, code or whatever.. is always greatly appreciated and very welcomed.