Does USCIS require a source of funds details from non-EB-5 investors in an EB-5 project?

The short answer to your question is yes, although it is not clear that USCIS has statutory authority to require such evidence, it is a good idea to include at least some evidence that the additional/required capital was in fact invested or will be invested and identify the source of the non-EB-5 funds.

Yes, the sources of the funds of non-EB-5 investors must be described in detail and necessary documentation must be provided. This is particularly needed if it appears that the funds in question is either gifts or loans to the EB-5 investors.

No.

No, they do not.

Typically no. But a full breakdown of the capital stack will be part of a proper EB-5 business plan.

No; only the EB-5 capital must be sourced.

Yes, particularly in a direct project. It is not generally an issue with regional center projects where corporate developers invest equity and get bank loans, but with non-regional center projects, USCIS has lately been asking us to source all capital in the deal, including non-EB-5 equity investors and non-institutional lenders.