Firstly, please post things like this in future as a "discussion" rather than as a "document".

My cert expires Feb. 2017, so I don't do the next level I will just renew my DCV (VCP6 I assume this time).

You will need to recertify prior to that date by passing a VCP level (or higher) exam - don't let your VCP expire.

I see on this page: Data Center Virtualization Certification Solution Track Page that my I should be considering VCAP6-DCV Design or VCAP6-DCV deploy. Correct?

You need to be either a VCP6-DCV holder, or a VCAP5 (DCA or DCD) holder before you can move to the VCAP6-DCV certifications - so your first step should be to achieve those.

What is the difference between the two exams?

Deployment is a live lab with tasks to perform, Design has you completing designs to certain guidelines and good practice.

How hard are they compared to the VCP5 exam?

The "A" in VCAP gives a clue - I did the VCP4-DCV then VCAP4-DCA and it was a significant step up. VCAP exams need special preparation, no doubt.

Do I need a VCP6 before I can go to VCAP6 or is my VCP5 ok?

As above, you either need VCP6-DCV, or at least one of the VCAP5 (DCA or DCD) first.