Safe, yes. If it doesn't fit, then this should be obvious before you even think about turning it on.
Happy - I doubt it. You'd need an extra inch of wheel travel to tension the blade and I doubt if a 12" saw has that much to spare. Have a look and see, but I don't think you'll be in luck.
If you can;t find blades to length of fthe shelf, then just have them made up to order. It costs about the same, or only slightly more, and you're usually getting a better grade of saw band. It also give you a much bigger range of blades to choose from, and a bandsaw is more versatile if you use the right blades - there is a difference.
If you don't have enough adjustment to take up the 1 inch you can cut the blade and remove the one inch. Then go to a local machine shop, most larger comercial bandsaws have a built in blade welder that will weld the blade back together. It only takes a few seconds and I am sure they will do it for free if they are decent.
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