Is using the alpha version of Percona 5.6 safe?
Big Percona fan here.  I'm really excited about a lot of 5.6 features (although many seem to be things Percona already provided).  At the same time there's no way i'm rolling out an alpha into production and no way I'm going back to stock and loosing thing I get from percona 5.5  Largely I suppose those "things" are related to information schema (which is just for my DBA satisfaction; not performance implications) as well as knowing I have a trusted xtrabackup situation going on w/ percona builds.

I'm personally waiting for Percona's 5.6 GA before even deploying to QA for evaluation.  

As for the fulltext feature you're wanting I'm of the opinion search like that is not the role of a relational database and should be delegated to a lucene solution such as an in house elastic search install, or searchify for a cloud based solution if you don't have the resources to manage your own search service.  

My opinion on your implementation isn't really an answer though, so to get to that more directly: Do not deploy alphas to production.  Alpha is the disclaimer saying "play around if you like but we're not sure we trust what we've built yet ourselves"