Ben's cutting resistance isn't that good I honestly think he might be a non factor. Reed AND sue are the real threats. Reed's Prep time matters. Sue might be able to do some damage but I'm not sure she has the reaction time.
When has Thing been cut besides adamantium? Also, Sue can put up a subconscious force field to protect herself and others. One instance was during Infinity War when she saved everyone from the Magus's surprise attack.