Tool and language proficiencies are not used. This includes Thieves Tool. Thieves tools checks use the character's sleight of hand modifier, and require a set of thieves tools which are consumed on use.
This is no longer true ...
It was changed in patch 3 or 4 i think, now it only consumes them on failed atempt.
//Edit:
You can have one ranged weapon set equipped and one melee weapon set equipped, and are able to freely switch between them as a free action an unlimited number of times per turn. This includes starting with a sword and shield equipped, switching to a crossbow for free, shooting at enemies, and switching back to sword and shield for the AC bonus before you end your turn.
This is also not true, you have AC bonus from shield the whole time ... so if AC bonus is all you want, you dont need to switch back ...
The only reason to switch back is for AOO.
It was unofficialy reported via emails from Larian to someone here on forum in the past that this thing will be changed on launch and AC from shield will be only calculated when shield is held in hand.
But it was not in build that people played in last even in Belgium ... so, who knows?

If you as an action throw a healing potion it will break and heal all targets in a small radius.
As far as i know, if you hit someone with that potion, they also get damage from being hit by an object ...
Not sure if that is still the case tho, since its several patches when i throwed potion last time.
Hide is currently a bonus action for all player characters. Recent footage seems to indicate that this will switch back to an action unless a feature (e.g. rogue's cunning action) gives you the option to hide as a bonus action.
This is true ... and it may be just my language barier ...
But readint it as it is, i would expect for Rogue to have option to hide as both Action or Bonus Action (put aside why would anyone do that) ... wich as far as i know, is not the case, since Rogue can only use Bonus Action to hide.
Prone: Your character cannot do anything while prone. Starting the turn while prone will cause you automatically stand up. Becoming prone during your turn automatically ends your turn.
Its also worth mentioning that when you knock your oponent prone, they quite often stands right up as if nothing happened.
*i stop reading at Paladin ... its a long one.*