Well as we know mass effect 2 inst out till the 26th i have the col addition pre-ordered and am sitting on thumbs for it. So i have been reading and watching anything and everything about it. I saw an interview on x play and one of the creators was saying that choices in the previous game influences the new one. so if Rex died in your play-through he is not there but if you didn't let him die he is still around. was not confirmed if still in your party or rejoin-able I'm sure he will be though.
The one appearing in the videos is named Grunt, If Wrex does return he won't be joining your squard again.
According to the Mass effect Wikia, Wrex can be found on the krogan homeworld,tuchanka, trying to breed a new generation of Krogan.
I just want to know if we are going to the Quarians planet and see Tali's face
No offense but did you play the first one? The Quarians don't have a planet they live in a bunch of ships called a floatillia, but I doubt they let outsiders on their ships they wear those suits because the cleaniness of the floatilla leads to them having almost no immune system.