No difference between timeframes. You can select anyone you want.

The robot is multicurrency EA. Metatrader 4 tester does not support multicurrency EAs. Thus for testing, use MT5 version and then use MT4 version for live trading. Both versions are same and MT5 Test results is enough for MT4 also.

Yes, All Forex Robots work when you open terminal and have connected to the internet.

Yes, There is some differences on frequency of trading and profits of each trade basket. This is because of slippages on real accounts. Using low latency brokers help to make larger profits.

Any broker with low latency and faster order execution time is suitable for this EA.