require suggestion for selections right connector type brand etc
Wanted to know Whatconnector should I use for motor,batt esc
Connectors from battery are 4mm banana
I fear using the wrong or hobbyking brand might lead to disaster 

What do you mean by that?
I have came across a lot of connectors being sold at many LHS and International Hobby Shops and i have always found connectors from HobbyKing being the top notch quality in each and every case.

How hard do you fly?

I use EC5 connectors on battery-esc and bullets on esc-motor. I can't recall exactly but bullets i use are either 5.5 or 6mm. 4 mm seems small. I anyway replace connectors that come with batteries with ec5 to standardize. This is what i have on my charging setup as well.

I have been using connectors from hobbyking. I used connectors from other hobby shops but could not notice significant difference. They have not failed on me. In fact its soldering that gifted me a crash once. If you get cranky with soldering may be you can have a look at APP connectors that require crimping. I have not used those.

Yeah EC5 will be a good option . You can even have a look on Supra connectors if you wish .