It will only be an abuse of process if they actually commenced legal proceedings ( ie issues a writ ) and then discontinued the proceedings.i don't believe they can as it would be an abuse of process
according to the lawyer
"Clubs including Leicester City, Leeds, Nottingham Forest and Southampton had also planned to bring proceedings against Everton, but later dropped their claims."
If they decided not to issue then , subject to limitation, they would be free to commence an action.