We skip Week 1 of Free Agent Offers:
Any players that get signed in Week 1 will have to be released.

During the Offseason Free Agent Stages:

YOU MUST OFFER PLAYERS A MINIMUM OF 2 YEARS
This is to prevent teams from offering a max 1 year deal to then resign him for cheaper next offseason.

There is no limit as to how many Free Agents a team may sign.