I personally wouldn't resign Fenton.
He doesn't command a starting spot anywhere in the field and is still prone to making the same mistakes like mis hitting nearly every cross he makes. Also, he seem incapable of beating a player on the outside which is essential for a attacking fullback or winger.
His lack of game awareness (he is always looking at his feet) is also a liability and one of the reasons he gets caught in possession so much.
I think Gulley has looked a better option this year, and probably comes with a smaller wage demand.
Fenton also hasn't scored in over 3 years... yes a lot of games have seen him play in the back line but he has also had time further up the field.
I remember watching his first ever game and thinking this young guy is class and eventually will be too good for this league.
Unfortunately he has never kicked on and if anything has regressed this year.