Not sure if I can answer the whole question, but yeah, you can get generic Attributes, when you're in a library symbol or title block, just go to Draw>Attribute and you can define it with whatever you like. Leave the value blank, and then when you insert the symbol in a project, right click, go to Edit Attributes, and fill in the Value with whatever you want displaying.
I didn't see that before. It looks like that only allows the creation of text attributes, where I want to create a box attribute and use several attributes inside that one.
Maybe a better approach would be to create a Parent/Child link, similar to relays. The detail could be the Parent symbol, and the tag would be the Child. This might work better for multiple quantities of tag, and allow for auto location tags near the detail symbol. I've already modified existing cross reference symbols, I'll see if I can make that work. If anyone has any tips for this approach, I would appreciate it.
Edit: It appears that cross references do not apply in cabinet layout drawings.