Even if they do, I have the feeling that the loser in this purchase is Twilio. I have a hard time imagining Skype or eventually Microsoft paying Twilio to handle their telephony infrastructure.
Skype already has its own infrastructure to support Voice and SMS. Iam pretty sure twilio will be out of the picture the moment the deals is done.
Well they will have to transfer over the phone numbers so they don't break backward compatibility. I don't quite know how that works with VoIP providers, but I think it's doable. Might slow things down a bit though.