First a disclaimer: I do not work as a programmer.
I went to California State University in the USA and graduated with honors. I attended full time while working full time (college + rent != heaven) and it was very difficult. I remember writing papers and studying until the early morning all of the time.
You can definitely do both, but there will be sacrifices to do both well. I was a hermit in those days and I lost friendships to make it work. I studied Business Economics. Looking back, only 25% of my time at University had anything to do with my degree and I found that to be disappointing and frustrating. Much of the time I was required to take courses that had nothing to do with my degree. General Education requirements they were called.
As far as doing FCC and p1xt’s guide at the same time, I think that is a great idea. I am toying with the idea of working through the guide and writing a blog while doing so. Perhaps a blog showing my learning path could be a nice bullet point on a resume, and also counter any negatives from not having a CS degree.
My last thoughts are this:
If it were me, in my location, I would commit completely to FCC and something like p1xt’s guide, learning as much as a I can as quickly as I can. I would then start the job hunting. Then, if I tried everything, and I could not find work BECAUSE every job required a degree, I would then consider the degree. Taking this route would take about a year, cost nothing, and has no guarantee of employment. However, going to University here takes 4 years, costs a fortune, and has no guarantee of employment.
I better stop writing. This is getting a little long.