Edited to add: If you actually click through to the terms of use, then go back to the sign up form, your details are deleted, but it seems like you can't open the ToU or privacy policy in a new window.
I'll put this link on the landing page too, once I've added a few more products to it.
I'll update the legal docs to open in a new page
The idea is that you refer customers to this site from your main website, but its still valid feedback
My personal preference is more subtle loading indicators near the element that triggered the interaction (the filter inputs themselves in this case) but that's probably subjective. I think at the very least you should keep filter bar visible while it's loading so that the element you're interacting with doesn't disappear while you're using it and pop back into view.