Does I2 Localization have PlayMaker support?

No, it doesn't at the moment. I don't have the PlayMaker plugin, so I haven't been able to create actions for it.

Nonetheless, To manage I2 Localization from PlayMaker, a custom action can be set to execute the language changing.

Also, in the next version, along with the Google Live Synchronization feature I will be introducing a centralized way of changing languages with custom inspector to get the supported languages and unify how its done in the different plugins.

Great, I added that to my to-do list.
Currently my plan for the next three releases are:

2.3- Google Live Synchronization + Speed Improvements

2.4- Reshaping the tools and general improvements to the interface

2.5- Crowd Localization (a common repository with thousands of the most common phrases used in games already localized by human translators in most languages)

2.6- Improvements of Modifiers, adding parameters to the translations and allowing Plural rules for each language.

The actual version numbers can change, but I'm planning around that schedule.
I think those features help more people, thats why I'm going to add the PlayMaker support in or after 2.7 unless more people are interested in PlayMaker than any of those features.

Thanks,
Frank

Currently, there is not built-in support for PlayMaker, actually it hasn't been requested too often so I have been prioritizing other features/fixes that have been requested more.
Nonetheless, integrating PlayMaker should be really easy and shouldn't take too long, so I will see if I can add that in between the next big features.
Also, I just added it to the roadmap, please, add your vote there to help prioritize that over the other tasks.
trello.com/c/bdaHZZDX/20-playmaker-support

Thanks,
Frank