You might actually want to consider Reactiflux as an option instead of a Slack group. Granted, a Slack group would work well for a smaller, goal-focused group, whereas Reactiflux is more of a general "discuss anything related to React and related tools" set of channels. That said, it'd definitely be possible for us to add a channel dedicated to this learning effort, and there's always plenty of people hanging around who can answer questions.
No problem either way, just wanted to toss out that as an option.
FYI, the Reactiflux invite link is available to anyone at http://www.reaactiflux.com . And, if anyone's interested, my "Practical Redux" blog series can be found in my blog at http://blog.isquaredsoftware.com .