Re: 5K training and CFFB
You have plenty of time to build the endurance for sure so no need to worry! I personally do my CFSB training and mainpage wod's while doing a 5km run in the mornings 5 out of 7 days (I personally never have issues with recovery but some do have troubles- if that is the case I would suggest running 2-3 times/week).
5km may sound like a large distance right now but in a short period of time your mindset will change for sure. In 10 weeks time depending on the effort you put forth you should easily be able to run it in under 24 minutes.
In respect to barefoot running, I started right off the bat with the same distances (Bad idea). I lasted the one run and found myself SORE the following few days after. You will want to start slow, but easily in 4-6 weeks time you can get accustomed to it.
I understand everyone is different, so what works for me might not work for other people (which is why I am offering you opinions on my personal experiences). If this was any help to you then mission success!
Have fun while training and you will reach your goals in a shorter time than you think!