We did the same but without phone numbers & sweets
Responses were positive, some neighbours suggested we should get together for a drink... so we organized an apero and about 70% of the neighbours (=people in same building) turned up. We were all in our thirties, and it was great fun.
We now have a normal relationship with our neighbours ie. we have a little chat every now and again, they can come to us if they need something or have a problem, and we go to them, but we're not like best friends.