Mass Effect Andromeda: Mr. Freeze build

Without mods MEA elemental and biotic explosions have a 4 second cooldown, during which explosions of the same kind can't be triggered. So I'd advice against a build focusing exclusively on Cryo explosions.

I found that the assault turret is not very usefull in the beginning of the game, due to its long cooldown and low health. So in combination with the point above, I would advice exchanging that with a different power in the beginning. E.g., A 1-point incinerate or energy drain.

Overload itself is not as effective against shields (in the beginning) as in the Trilogy. So maybe use a Remnant or Kett weapon (those have a 15% anti shield bonus) against shields.

Also: Due to the profile and on the fly switching capability of powers you really can mix and match as you like and can test out various builds during the same playthrough. I'd advice on having a dedicated profile for either maximum survivability or to dish out a lot of damage very fast using the combat type grenade power cell based abilities. These are also reasonably effective with only one point invested.

As for squadmates: My opinion is that it doesn't really matter who you bring. You can't control their powers yourself and the AI is not as good as advertised in detonating (or killing) anything. And when stuff gets really heated they often die in the worst locations. So take whoever you like.

Edit:
Also, Cryo beam's rank 6 'snap freeze' evolution works on all frozen targets, no matter what exactly froze them.

Sorry for the poor phrasing and confusion;
What I meant was that there is a cooldown per enemy and explosion type. So you can prime several targets and explode them at the same or different times. But each enemy has a 4 second 'cooldown' of its own, during which it can not be detonated with the same combo type.
So you can freeze an enemy, detonate that enemy, and if it survives it takes 4 seconds before another cryo explosion can be set of that enemy again. Using a different combo primer during that window works as usual and can be detonated.

Another thing I just remembered: Cryobeam and Cryo ammo apply the very same effect, which does not stack. The result is that using Cryo ammo on a build with freeze capabilities (on the same target) is useless, as cryo ammo does nothing else besides applying that effect*. It applies no bonus damage or something like that of its own.

*Well, it does change the damage type of guns from normal to cold. And all cold-primers apply a defence debuff for any incoming damage except for cold - damage.