What are the alternative processes of I-290bs when the I-829 is denied?

Very few I-829s are reversed on appeal. So, you can file an appeal, or a motion to reopen if there is new evidence, or challenge them in district court, if no NTA. If an NTA, you have a right to a hearing before a judge. You are still a permanent resident.

Can renew in front of the immigration judge or re-file and request leave for late-filing.

The AAO mostly affirms the USCIS decisions, unless there is a egregious error or an entirely new set of evidence. Ultimately, the I-829 will be adjudicated de novo in an immigration court.

The alternative is available in the immigration court removal proceedings. There, you can reassert you claim that the conditions should be removed. For errors, in fact or law, filing I-290-B is the best course. In answering your second question, success of an I-290B depends upon the circumstances of the decision and the manner of convincing the director and/or Administrative Appeals Office.

Potentially a lawsuit in federal court, depending on the circumstances.

Generally, there is no other option. Eventually, the USCIS will issue a notice to appear in removal proceedings, and you will get to renew the application in front of the immigration judge. It may be possible to take the denial to federal court, but many courts have already held that there is no jurisdiction, so the odds of success are not that great. Also, once you file the complaint, the USCIS usually issues the notice to appear. The USCIS sometimes takes years to issue the NTA, and must keep giving you stamps to extend your green card until there is a final order of removal. If possible, keep trying to create the jobs or solve the issues that were the basis of the denial because you may have some time before an immigration judge makes a decision on the renewed 829, and you may be able to solve the problem. How to do this is a very fact specific question, and you need to talk to an immigration attorney with experience in dealing with troubled EB-5 projects.

One can submit a motion to reopen or reconsider in the event of I-829 denial (on Form I-290B). One can also simply present the case again in front of an immigration judge. There is no appeal from an I-829 denial.