I've seen some players with santa beard & dread tail,santa beard&minihawk equipped at the same time, but i can't.

Why is that?

i'm not sure, but, perhaps they put it into a set and activate the set?

i tried that but it doesnt work :c

I had daimyo, surfer,Santa hat, Santa beard and tori hair at the same time once

There's certain pairs not equippable together

You cannot wear multiple items of the same type at one time.
Some users who had them equipped before that was implemented still have them, but if they activate something else now changes will apply to them too.

make sure that there not turned on in your Toribash settings