In MFN 30...how do I extend player and coach contracts before the season ends? Have cap space remaining this year and about 80% of the team becoming FA after next season.

If a player can be renegotiated then he will have a contract button on his player card. If they signed a one-year deal you won't be able to renegotiate without him hitting free agency, or if they signed in the current season you will have to wait until next year to renegotiate.