Basic Classes in Terms of Difficulty?

I sense a joke here somewhere   

I've been playing this game so long I sometimes forget that these things aren't always common knowledge. This is extremely sound advice, and I emboldened the bit about duration as it really is important for new players to grasp the importance of not using the cloak as a 'place to hide' - it's a damage booster, and game-mechanic cooldown manipulator, and should never be active for more than half a second unless you're capping a device.

I'd be lying if I said I don't do the same from time to time, especially if swamped, or when running towards a device which is some distance away - that's like a 'free' cycle of cloak, a lot of the time, though I do still try to time it so that I'm going back into cloak a pace or two from the device itself. When it comes to reviving teammates it all depends where they are precisely, and whether I can use soft cover when reviving them, so that I can hopefully use cloak instantaneously with the damage boost. More often than not I will just cloak on the way, though, like you've described. I guess my feeling is that anything goes in pursuit of objectives or medic responsibilities, but people remaining passively cloaked on escorts is my biggest bugbear because I think they think they're doing the right thing. You wouldn't do that, and I think you're a long way past running around in cloak looking for the enemies during normal gameplay, which I'm still conscious of with other players, particularly against Cerberus with their running commentary. 

I should also add that I spam Volus cloak like a mofo when I play the little guys. 

If you don't have much weaponery, you can still be very effective with the human soldier and CS:

1) set adrenaline mode for defence/shield -> to help when in trouble
2) set concussion shot for speed
3) forget the granade
4) all the rest for defence/shield recharge
5) basic AR (deadly in full auto)
6) ---> incendiary ammo <---- + some shield...

basically keep shooting until things get on fire, release concussion shot to fire explode all the thing, rinse, repeat every 1.5 seconds.. fully gold viable and Plat viable if you love the risks...

I think that if you are new you don't have the +5 grenade gear...

I, uhm, I have 6/12 Common mods, let alone all of them to V or any gear cards. I am also planning to test all the classes in Bronze, then play 100 bronze matches on my favorite guy, and then, maybe, just maybe, try Silver. I am not really seeing myself getting past that. Then, mabbe Andromeda is out, and wee, new zones, cuter monsters, same bronze! Yay!

... one thing that worries me is that the Infiltrator is considered the class to solo a disarm objective b/c of the cloak so I am wondering if that's one of those things that's only hard the first fifty times, heh.

I never detonate tech armor. I just set it up and leave it active for the entire game.

You put your finger on the thing right away!
The trick is that tactical cloak does not fight with other power's cooldown, it wraps other powers in it's own cooldown, you get 2 for 1 (1 for 2).
TC cooldown starts when you break cloak and ME3 TC allows power use while cloaked. When you cast from cloak whatever cooldown your power would have had, the TC cooldown replaces that with it's own (barring TC evolution 6A).
Additionally, TC damage bonuses are active for almost 2 seconds after breaking cloak, so you can use a power and shoot both.
And there is even more, TC cooldown is proportional to the length of time the cloak was active, if you brake cloak immediately after cloaking the cooldown is always as short as it would be with 200% weight bonus, regardless of your actual load. You get the listed TC cooldown only if you use the full length of the cloak. TC allows you to carry the heaviest weapons and still be able to cast powers.
Did I mention that powers also receive the TC damage bonuses?

The routine for the human infiltrator is that (assuming a semi-auto sniper rifle here)

A) you spot your target, it's not moving or you are confident you can hit:
1 cloak
2 shoot
3 cryoblast
4 shoot
do it right and 2,3,4 can all benefit the TC damage bonus, 4 also from the cryoblast debuff

B ) you spot your target it's moving, mook type
1 cloak
2 cryoblast
3 shoot
here cryoblast staggers the mook and allows you to line up your shot

You can add a sticky or two before decloaking, grenades do not break cloak.

I never detonate tech armor. I just set it up and leave it active for the entire game.