How will EB-5 program changes impact required investment amounts?

There is no answer to this question at the moment until the new rules are adopted. It is likely that cases filed prior to September 30, 2015 will be grandfathered.

At this point your guess is as good as mine, but the consensus among attorneys seems to indicate that if the exemplar project is filed before the September 30 date and is subsequently approved, then any investors joining will be treated under the old amount of $500,000. Whether or not Congress concurs is up in the air.

No one knows yet; most likely the effective date for the minimum investment will be the date of enactment.

This is a question that no one could answer definitively right now. There is a chance that Congress may vote to increase the minimum amount to $800,000 before September 30, 2015. If that happens, then unless they also insert the grandfathering provision for the projects that had had an exemplar filed to continue receiving the $500,000, the new investors will have to follow the new law. It is the consensus of "the people that know" that the only sure way to have the benefit of the $500,000 amount is to file the I-526 before the September 30 deadline.

We will not know for sure until the new rules come out, but I would expect that cases on file prior to September 30 will be grandfathered and new filings will need to comply with the new rules.