With so many ICOs flying around, can someone give a hint which team already has a working product and then launching an ICO, instead of the other way around.
Not recently.Infact,I don't know any in the crypto-scenario.If you look at it indirectly,bitcoin kinda did that.Didn't start as an ICO but got the most investors of the future. 
As i know the developers of social network running their own ICO (kin.kik.com) ,in few words it is cryptocurrency that can be used in social network.
Seems cool.Are they legit though ? Can't find them on bitcointalk.CommerceBlock has a working MVP used by customers - an invoicing system. They've implemented zero knowledge proofs on the original bitcoin blockchain but ultimately the underlying technology is blockchain agnostic and can be on any chain that uses homomorphic encryption keys. The invoicing system is a working POC of the underlying protocol layer that will evolve to provide services like derivatives trading, atomic swaps and token/asset creation. They've got a bip under review too. Almost ICO ready
Sounds so centralised to me.They have the working product ready without an hint of the innovation in the market ? Is their code-base open-sourced ?