1/. What do you think are best indicators for short term trading, as in t1, m1, m5, m15, m30?
The one between your ears. Indicators tell you what just happened but are no more useful than a roll of a pair dice.
2/. now are a plethora of systems out there, ninjatrader, multicharts, trade station, metatrader etc, which would you recommend and most reliable pairing with which broker? for both auto and manual
Ninja Trader is what I use. Stable platform and actually cheap to run long term. Ninja Trader brokerage is pretty competitive commission and margin wise and you get good support from them. I use Rosenthal, Collins as my broker. Commissions are competitive but margins are higher. They have the greatest market selection I could find anywhere. Could be too rich for your blood.
3/ any good signal providers you can recommend for live tradng?
It looks to me that you are looking for the easy way or a short cut with a signal provider. There are a few good ones and heaps of bad ones and you get what you pay for but you won't learn to be a trader that way. Take a look at https://www.collective2.com/ . Any system ever invented has a draw down, you just need to be able to ride thru that period.
Technically speaking those are platforms to develop systems. There are also systems that automatically create systems and write code for these platforms, e.g. Price Action Lab. I am investigating this latter approach as more time efficient and probably more productive than developing my own systems.