Yip,...changing name in your early days with him is absolutely fine as long as you are consistent in using the new name. Don't confuse him by using a combination of the new name and his former name. Won't be long before you've given him a nickname anyway !
He is a beauty, but I don't see any Staffie in him at all. Maybe you've misheard the rescue people and they were telling you that he may, possibly, be a Beddie / Collie type cross ? Sometimes the volunteers, and even staff, at the general dog rescue type places don't have a clue about Lurchers.
I'm willing to bet (only going by how he looks in the pictures) that Bob will have Deerhound (definitely not Wolfhound), greyhound and/or whippet, collie, and maybe Beddie bloodlines in him.
If you've never had a Lurcher before, can I recommend that you read a book called "The House Lurcher" written by Jackie Drakeford about twenty years ago ? She tells you what you need to know.
Another useful source of information will be the frequent Q&A section of the LurcherLink rescue website. https://www.lurcher.org/llink/forum/index.php
You're going to have so much fun with him.
This one isn't mine, but I love the picture...hope it works...