The two month follow-up should send out OK, just keep in mind that each distribution will be relative to the date that person completed the pre-survey. As a result, the follow-up surveys will not be distributed at the same time. For instance, if Respondent A completes the pre-survey on August 1, they will receive the follow-up on or around October 1. But if Respondent B completes the pre-survey on August 31, they will get the follow-up around October 31.
The design of the weekly survey will largely depend upon how respondents are contacted for the pre-survey (an email invitation with a unique link, or are they using an anonymous link), how long the pre-survey data collection window is open, and whether respondents need to complete each weekly survey at the same time or not.

Makes sense! The pre-survey link would be anonymous and open for 1 year. While we want to use a general link for that survey, the survey itself is not anonymous. Essentially, we want to use a list-serve to recruit. The weekly survey would ideally be sent every Wednesday to an individual beginning on the first Wednesday after they complete the pre-survey. Would this be possible? If not, we could potentially design the pre-survey to have unique links.

Thanks!

I haven't used Triggers or Actions that much for survey distribution; I don't know that there is an automated way to send a survey on a fixed day every week using either of those features. (My recollection is that the distribution date is relative to the date the response was submitted, in terms of number of days.) I think the best you can do is compile weekly email lists from the previous 7 days' respondents and send those out each Wednesday using email distributions.