Which Legendary Bird you can encounter depends on which Starter you have picked, and since you have Froakie, you will encounter Moltres. The Legendary Bird that will appear depends on your Starter, and are as is listed below:
Source: Serebii.net and Experience
You will only get Moltres.
Source: I started with Froakie
You only get one of them. so I think you only get molters.