Nex 5r or 6 studio

I can't decide which to go for the 5r or the 6.

I sold my 5n which I liked but wanted to give the hybrid focasing a try.  I am thinking of starting to take my own family portraits instead of paying someone up to $500.  I thought they would have thousands of dollars of gear for a professional business but the guy was using a cheaper model xt canon i think with a 15-85mm lens.  I can get by without the viewfinder but the hotshoe on the 6 is where I am confused.  Can I buy a couple of speedflash units and hook one up to the 6 or the 5r and the other on a stand.  I see there is an adapter for the 5r but does it turn the 5r into the 6 for the flash or is there more options in the 6 to do special things for the flash like handling a second flash.  The 6 would be nice but I am thinking more of size than the $200 increase.  I really liked the size of the 5.  Any help would be great.  I am not looking for a multi hundred dollar external flash but could I just buy a couple used canon ones off craigslist?

Sorry I am new to the whole external flash in photography.     Thanks