Planning Bachelor Degree (through 1 of the Big 3)

[allvia]

The option with AU is very interesting for me. I have 160 graded credits from a German University. It has been evaluated by a credential evaluation agency. Could I get the 3 year bachelor degree in general studies from AU. Then transfer that degree to TESU as source 1 and transfer some other credits from my 160 credits as source 2 and then just get a 4 year bachelor with just doing the capstone?

It doesn't work that way (for any of the Big3); what you're talking about is called credit laundering.  TESU doesn't take a degree as a block transfer, they take credits individually and from their original source only.