Master Plan

Master Plan
This ability allows the user and up to four
other recipients to each gain an additional
use of a periodic skill for the next encounter
in which they participate after thirty seconds
of concentration spent discussing a plan for
the encounter.
Periodic (Unique), Procedure, Influential (Social)

1) Is there a limit to the number of times a single person can be affected by this skill Simultaneously? I.E. Can I Spend the roleplay with my friends, grant them all an extra use of stealth, and then spend another 30 seconds to give the same people another use of stealth?

You may only benefit from it once at a time. However once you use that Stealth (and are no longer presently under its effect), you can get back together with the Racketeer and benefit from a second Master Plan.