A lot of SPs use clear face shots and those girls would not mind if you asked. Many SPs also allow filming for an extra 100 or so. They also have contracts and release forms to sign. However there's plenty who would do it.
The average girl in porn is not making much at all. A good SP makes way more. There are girls entering porn doing multi hour shoots for 500 or around there.
The thing is the porn industry will take anyone, will you get solid steady work? Not likely. Also with porn the women are having sex with men they are also physically attracted to and who are well endowed.
A popular traveling escort or even a local fav who is popular can easily do 4 days of work and earn 600-900 a day.
However for a girl doing porn it is really hard to find work that will pay you 10-20k a month for a sustainable amount of time. A good SP can easily do 1k a day as that's only 3-4 clients.
Now I know a lot of the shitty SPs will debate that but yea dont listen to them. The next time you book one of the popular visting girls online and you have one of those forms where you can pick your time and see times that can't be booked because it's an already booked hour. Then you see how busy some girls can easily get. A good touring girl should have no problem getting 4-5 a day.
There are some really good documentaries from the bbc on porn in the US and overseas where they follow around new commers and really show what it's really like. Just cuz a girls done porn dosent mean she's a porn star.