You can buy furniture and lay it down in a certain place (your house) and be able to move it.: Correct. You can do this with variables. It's just uber hard...for me.
If you pay off a loan your house size expands: I thought of switches here. If switches don't work, then variables once again!
Everytime you talk to someone they say something diffrent: Variables come back. I assume there is a randomizer thing in the Variable Operation window, so this kind of thing would be pretty simple but pretty long at the same time.
A day working system: Scripts. Or you can use the timer and stuff, but that's boring.
Set date, time, and year : Variables. Or scripts.
Diffrent clothes and custom clothes: Different clothes is simple...for me, I would change the Character Set, but custom clothes seems to be a very hard matter, especially since I haven't seen any kind of this in the RPG Making world (Ability to create custom stuff). It should be possible...with a hefty amount of work.
Town Travel: Scripts. If you can make a script that allows you to go online, whoop-de-do!
Shop Randamazation: I would say variables in this matter.
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Your idea seems very interesting and original. If you are making this kind of thing, I would really want to play it. *drools*