Is your feature request related to a problem? Please describe.
Custom anchoring is great, but if I want to anchor clones to different relative points on the same region (not just different regions for each clone), then it's more difficult to achieve.

Describe the solution you'd like
Some way of returning the frame position and relative position when returning the frame I want to custom-anchor to. If custom x,y offsets could be returned as well, that would be even more helpful.

I don't think we want that. We use the same "design" for anchoring individual auras as we use for customizing dynamic groups. And for dynamic groups, that doesn't fit and thus imho we shouldn't add it to individual auras, as it has a very niche benefit.