If you have 2 part time devs with a manager giving them the info in the meeting, that's 3 people spending time, and the two part-time devs won't have 100% overlap of information needed and questions asked and answered (and if you have two separate meetings with each PT, then they won't have access to the questions/answers discussed with the other dev _in case_ they need it).
Additionally, everyone can focus on producing and consuming information in the downtime between focus-work sessions, without interrupting flow at someone else's convenience.
In all cases, quality documentation is more likely to produce accurate information transfer with less time wasted by everyone involved.