5) If the EB-5 project the EB-5 investor invests in goes bankrupt, does that mean they can no longer get a green card through this petition?

It depends. The most important criterion here is whether the JCE created the requisite 10+ jobs per investor attributable to their investment. For example, your clients should have no issue provided the JCE filled all of the jobs and deployed all of the funds on the project. If the JCE did not fill the requisite jobs, or if they did not deploy all of the funds, then your clients might have an issue unless their attorney could argue that their funds went into the project to create the requisite ten jobs attributable to them.