Unless the guns have been made to work specifically with the suits (something this team has NOT been issued with), I am going to say no. But it all depends, I am still toying with the idea of giving us assault rifles, but I'd rather us (as previously mentioned) have to work for it later.
The HUD can highlight targets for you, and track them for a short time while out of sight (few seconds), but aiming is done the good old fashioned way.
Please remember that this is NOT the nano suit from Crysis, it is cutting edge but not stupidly so. No MAXIMUM ARMOUR mode. If you are hurt the suit can administer some medical treatment to keep you alive and going, or kill the pain until the Medic or a medically trained sqaud member comes along. These suits can withstand an indirect nuclear blast even damaged, but they aren't going to last forever. They should last the run of the game at any rate, scratched, dented, torn, and with a dead battery (can be charged manually and by other methods).
We will find out stuff as we invent it in the story if that makes sense, if we set things with the technology too far ahead then we could end up cornering ourselved, because we said it couldn't do something.
In terms of an ammo counter, it may possibly eventually show a percentage of guessed ammo, remaining after using the gun for some time and having reloaded it several times. Not accurate however. And if possible, we are mostly all soldiers, the ammo counter would be an aid, and something most of us won't use or need. We'd be better able to guess remaining ammo, than the suit.
And radar would be really inneffective.