I'd like to know from native speakers what would they call or what slang would they use for a person who cries easily watching even the silliest of movies (meaning very little drama). For example, watching Home Alone when Kevin meets his family again.
an emotional person is prone to emotions.
emotional - (adjective) "readily affected with or stirred by emotion: an emotional person who often weeps."
I'd normally call them a sap. Meaning someone who is overly emotional and cries at the slightest sad thing. However I can't find that definition in the dictionaries I looked at. I will also note that a "sappy" movie is one that plays to one's emotions in an effort to elicit a response- like crying:
For example here's sappy used "in the wild" (thanks @Conrado):
Everyone needs a good cry every now and then. Especially since it’s summer and we have plenty of time on our hands to watch sappy movies, eat chocolates and bury our sorrows.