Is it right to say while distributing sweets on the b'day ocassion - "Thanks! for the bonhomie wishes"
As snailboat points it out, the word bonhomie is not normally used to convey the 'thanks!' for any wishes.
In your sentence, the word seems to be used as a adjective, whereas it's actually a noun.
bonhomie - a feeling of cheerful friendship
Down there, the noun is used this way
There was a casual bonhomie between the actors at rehearsals.
If you see your sentence and fit in this word there, it won't look natural.
In my opinion, you should keep it short and simple - "Thanks for your birthday wishes."
I assume that the sweet is distributed when someone wishes to a birthday boy/girl here.
Looking at your comment here, it seems that you are in search for a proper adjective to be put before the word 'wishes'; you need to emphasize it. Well, in that case, there could be many options including warm, heartily, wonderful, lovely...and so on.