Well, there are ambidextrous handguns - they will all typically eject to the right no matter what. However, some have a magazine release that either works on both sides, or the magazine release can be changed to work left handed (like a Beretta 92 can). Some guns also have an ambidextrous slide release. More guns have this now than in years past, but its still not that widespread. Off hand, I can think of some HKs that have this. I think the new PPQ might have it as well.
Shooting with your dominant hand will be much easier no matter what. If you have to change because of a physical limitation - it can be done. But most people really suck when shooting a handgun left handed if they are right handed.
As you are a new beginner, I think you will be making it even 2x as hard on yourself if you try to compound being a new shooter AND trying to shoot left handed.
The smaller the caliber combined with the larger the gun will make recoil less (making it easier to shoot). However, as we discussed before - you said you didn't want a revolver but wanted to go with a semi auto. So, no matter how many guns you put on your list, you need to try them all to make sure you have the hand strength to work the slide by hand. That will probably eliminate many guns that you do have on your list.
Also, as for your friend's new gun... 9mm Keltecs are NOT fun guns to shoot. I think that's a terrible first gun for a woman who has never shot a gun before in her life... I think she will be very surprised after her first range trip, unfortunately.
Of the ones you mentioned, The Stoeger Cougar 9mm, The Ruger P95 and the Beretta PX4 (fullsize) will have the least recoil... The Ruger should be the cheapest. The Beretta PX4 is my personal favorite. But, you do live in New Jersey, and you are paying much more for guns there than we are (as we've discussed before as well)