If the guys you placed on the transfer list don't sell, you'll be able to fire them once they're no longer on the transfer list (tomorrow afternoon, it looks like). Each listing is only for three days, at which time when the bidding is over, the player either goes to the new team or, if nobody bid, he stays with the old team.
Firing the two players you have listed would bring your salaries just under the salary floor for our league (welcome, btw!), but only by about $500 or so. If you had planned on getting rid of additional players, though, it wouldn't save you any more money since if your salary is under the floor, you pay the floor each week instead.