Suresh is Colonel Brandon.
Purab is the Kumkum Bhagya version of John Willoughby but the character is slightly inspired from Edward Ferrars... He is "secretly" engaged to a girl Abhi picked, but he is going to fall for Bulbul and out of respect and love for Abhi, he is going to break Bulbul's heart and marry the girl Abhi decided. Which would probably start the Suresh-Bulbul love story. Like John Willoughby, he is there to show Bulbul that there is more to love than being romantic, and that Suresh is the perfect man for her.
Akash is inspired from John Willoughby... he is money minded though he genuinely feels for Rachna (that story inspired from John-Marianne), he is ready to ditch her and marry someone else for money like in the book, but here most probably either Abhi would force him to marry Rachna or his ditching her would lead to Abhi-Pragya love story..
Abhi is the Kumkum Bhagya version of Edward Ferrars... He is Pragya (Elinor)'s pair... He is going to be passionately in love with her... and like Edward he would be involved with another girl at the same time which would stop him from confessing his love for her for a while, I guess . only difference everyone has an inclination that there is a girl in Abhi's life, and the way his Dadi keeps going on and on about what happens when he loses his money... looks like Abhi would end up losing money like Edward Ferrars, and like Elinor, Pragya would support him then.
This is what I gathered from everything...