I am having trouble with a trying to roll fields from multiple tables up into one ""overview"" table.

I'm not sure if I fully understand your question but I will try to answer.  

If you have  a table which already has a relationship built, and it is the child in that relationship, and that same table needs to be a child in Relationship #2, when you go to make the next relationship, that field that you already used in relationship #1 will not be available to use again.

So just make a field called [my field mirror] which a formula equal to the field that you need, and it will be available to use in a 2nd relationship.