You won't have rear camber of 0.
I've seen "standard" cars with -1.5 on one side and +1 on the other, time and the original broad Honda set up tolerances saw to that.
The Honda tolerances on the geometry of the EP3 (and the FN2 later for that matter) from the factory were very broad. This means that cars can go out with a geometry set-up that is far from ideal. After a few years of things settling they can go even further out. This is why having the FRSU done makes such a big difference to the handling.
Right onto the meat of it. Having the FRSU done on the front improves front end grip and response on turn into bends, great. Having the FRSU done on the rear of the car makes the rear more stable, gives more grip and makes it more predictable.
If you look at any car manufacturer over the past 10-15 years, they've set their cars up to inherently have a bit of under-steer, they call it safety under-steer. It is often easier for the average driver to correct and get out of a situation where the car is under-steering rather than over-steering, because let's face it we're not all a Sebastian Leob or a Lewis Hamilton.
The point of that is, that if you only get the front done, you are improving the front end grip but leaving the rear as is and the rear is pretty snappy and prone to coming out wildly on the EP3 anyway. The FRSU usually puts around 1 degree toe in on the rear which helps improve the rear grip and means you have to push a lot more to get the back end to come out, but like I said it is more predictable rather than the snap and it's gone feeling before.
Another factor is that the rears tyres do suffer badly if the OEM geometry is out, so again it's another reason to get it done.
At the end of the day it is up to you, however since you have asked, I would hand on heart only recommend the full FRSU! Just get it all done at the same time, stick it on a credit card and pay it off next payday before you get charged any interest.
Yes, your local 4 wheel alignment place will be able to do the set up once you have the camber bolts and rear camber arms.