Which followers have helmets and suits?

Which is something I didn't like because, as I said, I like to see faces when people are talking with each other.  My preference probably has a bit to do with becoming a little hard of hearing (even though lip animations aren't that great).  The "off in conversations" mode doesn't make sense either since the helmets just vanish into thin air and then reappear.  There are only a few scenes in any of the games where they show the helmet being removed in order to talk. 

At any rate, in ME:A they are seldom "in the vacuum of space"; but are on planets that are ultimately meant to be habitable (with some improvements required) or in space ships where, even today, astronauts onboard the space station float around in T-shirts and without breathing gear on.  PeeBee's navel being exposed to the cold on Voeld - well, I live in Canada and have seen teens running about in T-shirts in -30C weather.  Not smart to be sure, but that doesn't seem to stop them.  Maybe Asari don't feel the cold as easily as humans.  Certainly the Angara had adapted to Voeld's climate to a large degree (we are told as much when we talk with the two lookouts just outside the Resistance Base.  I don't think Asari tolerance to cold was something ever mentioned previously in the lore, so IMO, it could be used as an explanation for it.

As I said, I've seen teenagers in Canada running around in -30C temperatures in T-shirts.  A few years ago when the short T-shirts were fashionable for the girls, I'd see a ton of bare navels in the winter time.  The temperature on Voeld, before activating the vaults was -40C and raises  11 degrees after the vault is activated... which means it gets warmer than some Canadian winter days.  We also don't know what high-tech properties Peebee's jacket has.  People here use little chemical heat packs inside their gloves and such, so it's possible her jacket has a heat feature that can provide some radiant heat to her navel area without actually covering it.  What's ridiculous is Ryder complaining incessantly about the heat on Elaaden.  One would think a suit that completely covers him/her and is designed to make it possible for a human to survive the "vacuum of space" would have an ability to regulate temperature inside the suit... since the temperatures in space vary to far greater extremes than shown on either Voeld or Elaaden.