the version where he is one of the best fighters yeah, but all the tech he has who knows maybe maybe not. for sure batman the version where he's hurting amazo and taking on deathstroke wont work in fact the guy would truly end up like in the kingdom comic wearing metal exo skelton cause he's been battered so many times but then again i may be wrong.
It would be impossible. Most of the things you see in comics aren't really able to be done by humans. Think about it. Can a human being master martial arts, be that smart, cunning, etc. and stay in peak condition for years on end, yet suffer from an insane psychological trauma, and then not kill someone?
Nope, but that's why it's comics. Suspension of Disbelief is a wonderful thing.
I would say yes. Whoever this "Batman" would be he really dont have to master all martial arts styles but if he has been training since very young is very possible to master a few ones. Study in diffrent areas along the way to become a great detective and he'll be ready by his the time he is 30. Then If he is a billionaire like Bruce he could pay someone to supped up an already fast car (i.e Bugatti Veyron). He dont have to last 60 years or whatever but he could do a lot in a 10 yr period.
Law enforcement will be a whole different deal and I dont know if he would be able to get away since nowadays there are GPS systems, satellites, cameras in traffic lights(too much 24, I know). Unless he has a someone hacking law enforcement every time he goes out, someone with Oracle hacking skillz.