Hey Goldenoldie, I know this sounds strange, but is it possible for me to get a WC if Im in the Houston 250 ATP Semifinals?
No, you can only get a SE for reaching the final.
As the QD for Athens will be made before the SF results are known for Houston, you will be included in the QD, but a space will be left in the MD.
You will need to send picks for Athens QR1. If you reach the Houston final your picks won't count, your opponent will get a walkover, and you will go into the Athens MD.
If you don't reach the Houston final you will play your Athens qualifying match as normal and an extra LL will go into the MD.
This sounds a lot more complicated than it really is!