As far as I am concerned there are no magic numbers for chicken space required. A lot of people on this forum use 4 square feet in the coop along with 10 square feet in the run, but there are just so many variables in flock make-up, management techniques, climate, urban versus rural, and who knows how many other things that we can't have one number that is perfect for all of us. That 4 and 10 will keep almost everybody out of trouble and is actually excessive for the absolute minimum requirements for many of us, but occasionally even that gives problems. A couple of things I like to mention is that the more space I give them, the less hard I have to work to maintain them and the more flexibility I have to manage things that come up.
With all that said, I think you will be in good shape until you decide to hatch out more chicks. Even then, you might be OK as long as you don't overdo it.
One thing I'd consider. In Massachusetts, you will probably get some snow. Chickens usually don't like snow when they first see it and don't go out into it until they get used to it, which can take several days for mine. Mine will go out and forage and sun bathe in zero degrees Fahrenheit weather, but they don't like a cold wind. If a cold wind hits them, they get into shelter.
I'd suggest you look at how you could create an area that gives them wind protection and keeps the snow out of a portion of the run so they can more easily get outside in bad weather. Some people use tarps and such for that, but it sounds like you are in an urban area and "cute" may be very important to you and your relationship with your neighbors. You may need to be a bit careful how you do this.
I have a corner created by the coop and a wooden gate that gives them a good spot outside for wind protection. I have a roof over part of my run, but snow does blow in from the side. In my climate, that happens so seldom it is not worth fixing.
But all in all, for five chickens what you have sounds great. I think you will be fine.
