Manifort's big problem is that most of the new charges are based on co-actions with Gates -financing based "paper" charges - prosecution will display bank account A, invoice B, memorandum C. et al. Claiming that Gates is lying or there are other explanations, would be next to impossible.
Mueller is also currently interviewing that fella, who is alleged to have given Manifort 18M, for a potential WH posting. The walls are absolutely closing in on him.