But what would happen if a team tried to go for two points. Can they call a fake, and try to score from 15 yards out? If they reach the endzone, it still worth 2 points? Or can they declare their intentions, and go for the endzone from the 2 yard line? Or if they are desperate (last seconds of match, two points down), would they have to call a regular play from 15 yards out to score?
Quoted from the Washington Post
In the NFL’s preseason experiment, the ball will be placed at the 15-yard line, making for a 33-yard extra point. Two-point conversion attempts will continue to come from the 2-yard line.
But the main point: Yes, if this were to actually be implemented, 2 point conversions would remain the same.
As far as faking from the extra point spot, as @Duncan says, as far as the rule states at the moment, nothing else changes really besides the yard you hike the ball from for an extra point. So of course, if you were going to go for 2, you'd make it clear and hike from the 2 rather than trying to trick them and starting 13 yards further back.
I do see 20 yard extra point hikes referenced in a few articles, but generally it's 15 yards. Since this is just an experiment, I'm sure the NFL was rumoring several different distances they might consider.