I am not so sure that the 2 out of 5 rule applies to a loss situation--you/we may need more homework.
I'm not sure sure you do not lose the ability to qualify the loss under that act if the property is not your personal residence at time you actually sell it -you need more homework.
I'm more familiar with 2 out of 5 rule in context of exemption of true gain on sale. ( I could be missing it in contect of gain as to forgivness of debt)
If you miss the deadline you miss it! And I thought for now the act only covered 2007-09 .
You may need to sort out if you can/need tomove back in to reestablish primay residency status.
Rental use requires you account for depreciation issues whether you took it or not.
If you suffer a loss on a business investment AFTER it was in business use that may be a deductible business loss
I think you better sit down with a tax pro to sort out what fits where and when.