Either party can withdraw their offer/counter offer prior to execution.This happens pretty often in competitive markets and is always a bummer.

I can see getting a substantial discount there, though even that may be limited somewhat now, since rehabbing/flipping properties seems to have become rather popular since the last bubble / HGTV, so I suppose there's competition there, too.

That is the competition for renters in this area.

The benefit is the competition is more class A or B type units.

What is your competition offering?

If you're sending the same mailer as your competition, you can expect a lower than possible response rate.  

Of course, we just want to try to get the best deal possible as this is our first flip and there is sooooo much competition in our area.I've read and watched the webinar about tax (lien) sales and I have been learning about some of the things to be aware of (THANK YOU, BP!).

I think the folks were pretty stunned that I would do that... but my competition would not do it.. they were old school phone fax and mail..

The level of competition here has increased in western WA.  

There may be more competition in that area but do not consider that a problem for you.