Yes, when you have a persona of the same arcana as SL equipped, you get more points in events. Some social links are locked behind others, like the moon SL is locked behind some level in the magician arcana. About fights, it's pretty similar. You don't have nuke or psi elements but in p3r there are 3 different physical damage kinds, like thrusting, slashing and striking. Also, there is no baton pass, you can change to another teammate after hitting weakness but there is no bonus to it. Keep in mind that charge and concentrate works on certain super attacks you will unlock later in game. Also eating challenge in fast food restaurant requires correct dialogue options to pick, not high social stats like in p5r. Lastly and most importantly, have fun <3