Veer ji i have made a thread on this topic and here is the link with the full information.
But here is a quick summary
Bhai Daya Singh Is a avtar of Ram Chander's son Luv
Bhai Dharam Singh is a Bhagat from Delhi (couldn't understand it)
Bhai Himmat Singh is from jagannath puri satyug (couldn't understand it)
Bhai Mohkam Singh is dwarka (couldn't understand it)
Bhai Sahib Singh is sain bhagat de avatar
Bhai Mokham Singh Ji was the avtar of Bhagat Namdev Ji I think that's what Sant Ji said, Bhai Dharam Singh Ji was Bhagat Dhanna Ji 's avtar and Bhai Himmat Singh Ji (i had trouble understanding it totally too)