This has been discussed before. A President can pardon people for crimes they may be charged with in the future.
Not that there is no precedent of course (Nixon).
There is no extradition request to the U.S., so when fighting an extradition to U.S., Snowden is beating a straw man.
Commutation is reduction of sentence, it can only happen after conviction.
> Like 97% of the cases that go to prosecution in this country, let him plea to a lesser crime
Is there any indication that Snowden has any interest in pleading guilty to anything?