I normally allow extra children but not the other without an addendum. 

Here's the link: http://get.biggerpockets.com/flippingbook/Make sure you check out my blog post (link in signature box) for some extra motivation for your real estate journey.

If you could take your money and make another 30k that year by doing nothing extra but starting construction earlier.

Can I give it them exactly 60 days before the year lease and those extra two weeks ends- ie. 46 days before that year end expires. 

The land might not be useable under any situation and you are paying extra taxes each year for nothing. 

If those extra payments are going to move the numbers below your minimum investment criteria, then no, it is a poor way of funding a down payment.

Unless you can charge a premium on rent for having hardwoods that is enough to offset the extra cost of install, perhaps consider vinyl or laminate? 

I am self-employed, and even though I have a sparkly credit rating and plenty of savings to make the cut, meeting the underwriters' requests turned into an extra part-time job for several weeks.

(which I don't think she is) It would also add a ton of extra closing costs that wouldn't have been involved when whole-selling.

You're not required to do anything extra.