Can two female crested geckos live together?

Well, for a 35 gallon tank you should have two geckos at the most. If it would just be two geckos then it may be okay, however they have to be about the same size. If you put a baby with an adult (female or not) they will eat the baby. If its not a baby but significantly smaller the larger gecko may bully the smaller one. In addition, if it is a new gecko added to your collection than you should give it a quarantine period of 30 days (at the least) to make sure it is not infected with any sort of parasites that may spread to your other geckos. This means keeping your gecko in a separate cage and handling it as well as cleaning its cage last (so you don't spread the possible diseases).

So:

If there would only be two geckos..

And they are both females (males and females will mate; males and males will fight) ..

And they are about the same size..

And you quarantined it for atleast 30 days if its a new addition..

Then yes, and if it is yes than after you get the gecko make sure you check them for aggression. If one loses significant weight or have scars you will have to separate them.

yes just make sure you dont see them wrestiling