The reason for return is you biggest hurdle. Didn't you mention in another post that she has a son. Of course you wouldn't want to jeopardise any further applications by her not returning. You could go into this and that that she looks after her parents.
If its refused you address the reasons why and apply again you don't have to wait 6 months.
As long as you show details of the house and its big enough it shouldn't be a problem, unless your ex was living there as well. lol
Are you sure January is the best time for her to visit seeing how cold it is. It could put her off wanting to stay.