How would your boys be with an MC that likes to play fight? Would they let her win? Would they refuse all together?
Sans: He does enjoy play fighting - but only the relaxed kind, and exclusively with people he really really likes. It's a lot of physical contact for him. You have no idea how much of a privilege it is that he engages with you like that, tussling and teasing when he normally can't even stand to sit too close to somebody. When the play fighting comes out, it's a very reliable sign you're one of his 'forever people'.
Oh, he'll let you win alright; oh noooo, he's pinned under a hot human, oh nooooooo truly he is defeated. He's totally dead, only a kiss can bring him back. It's the only way. Right on the mouth, please.
Red: Play fighting might as well be one of his love languages. He likes it rough, after all. A bonus of having to do a lot of actual fighting while underground is he's very good at controlling his strength, he's aware of his body, he knows exactly when to apply pressure and when to ease off. Red is probably the safest and most fun skeleton to play fight with; he has an extremely gentle nature underneath all that swagger and he loves letting it out.
He enjoys casual displays of his strength. He'll let you think you're winning, then flip you onto your back, or pick you up and toss you over his shoulder, easily disarming you. Though like Sans, he's also not adverse to "losing" and having his very hot human love interest all over him. He'll happily ruin the moment with sexual remarks too.
Skull: He loves play fighting.
... Well... he likes when you TRY to play fight. He appreciates the effort, he likes any consensual contact and anything that shows you're not scared of him. He won't be doing all that much fighting, he's far too big, as soon as he even gently play fights he immediately wins. But he'll act the part, faux collapsing when you've defeated him, even if it's as convincing as a bear pretending to be defeated by a small cat.
You'll win every time. You've gotta understand, though, that play fighting with Skull is playing with fire. He'll get swept up in how cute you look when you have that victorious glimmer in your eyes, and his cute aggression will rapidly rise. You'll end up crushed by cuddles sooner or later.
