If by available, you mean able to place your house there, anywhere works.1) How do you know which house/area is still available or not.
Buying a larger leveled house gives you higher interest. When you start the game, you have an interest rate of 0.3, it can get up to 0.5.2) How many levels of houses are there and does the level have any other significance then the sheer size of the house alone?
No. But your characters level does have to be the same or higher then the house level.3) Do I have to purchase a lvl 1 house in order to advance to a lvl 2 house?
For each level of the house you have, you lose 10k. A level 1 house costs 50k to buy, sell it and you get 40k. At a level 2 house, it costs 100k, and you lose 20k, etc.4) Can I late sell my house If I dont feel the need for it anymore? If so would it be to a player or npc what kinda returns do I get on my investment?