Q) Without going through the Lot/house design menus...is there a way that one can just sit one house on one lot without setting up house templates etc..?

A) Graphically, yes by using the Draw a Multisided Building option in the Drawing Utilities sub menu - to be able to take advantage of the house routines and report writing in the subdivision portion of the program - no, not at present time but this may come in the future.