Hi Michael..You could try this way as well..

You post the link of Your site on Facebook (group or private message, or paid ad) with description similar to WA (if You don't want to mention already in Faceebook that it is about WA(, then when the visitor of Your ad in Facebook click on your link posted there, and land on Your web site, then You can create "killing" ad or review on your landing site and the prospect can be transferred to WA and You get referral.

Also, there are some programs which are offering re-direct links (You can Google them), but this approach is more "tricky" and maybe the prospect wouldn't like it. I think it is better way to use the method described above.

My question: why do You want to use re-direct links, instead just post direct affiliate link for WA. You can post both links...of your web site and of WA.

I hope it helps ...

Yes. And no.
Yes - you can achieve it by creating a good WA review on your site and making it a "go to" page for your advertising. If you make it good people will click on WA link and sign in = you get a referral.
No - there is no other way of doing it as far as I know.