Who can train IATF 1649 internal auditor

There is no requirement in the standard for internal auditors to be trained by exemplar certified organization. The only requirement in this regard is for organization to retain documented information about the trainer competency, but it refers to the trainer alone, not to the organization to which the trainer belongs.

How long do you have to repeal a Minor Finding with your registrar?

I assume you are asking, how much time does the organization have to remove minor nonconformity found during the certification audit. Usually the deadline for removing nonconformities is agreed with the certification body, and it depends on the scale of the nonconformity. In case of minor nonconformities, the deadline is usually one week, but there is no rule that defines the time frame explicitly.