Problems with game

i’ve stopped trying on my old game and worked on to something i’m more interested in. i’m trying to make an Earthbound game and i got all the walking sprites for every character in it, i even found houses, and buildings from the games i have a number of questions to ask and then I’ll stop asking so many questions and will be able to work on it for a while.
number 1) I want to use the actual houses buildings ECT. i have put the buildings behind my character but for some reason it is white from around my character how would i switch it so it could show the whole building accept where my character, i have them on diffrent layers but it still is white in some area. someone help?
number 2) when you walk over and pick up an item or walk over on a door and it opens into the building
number 3) random battles, i know how to put the system itself up but how would i make it so when you walk after a while i random battle happen.
number 4) putting in an inventory so when you equip it it actually stays and disequip ECT. also A “party” as in a group of people following you as you go through the game, like in the Earthbound game its self when they follow behind you
number 5) changing the day to night, afternoon ect. after a certain time (i think i might be able to accomplish this by myself)
number 6) when you walk out of the screen and it moves on to the next part, i think its called scrolling enviroment.
i think thats all i’ll need, sorry for being such a noob.