So sorry for your loss. I think its wonderdful that you are planning on opening your heart up to another boxer
I would keep looking. There have been mixed reviews on Landos Boxers.
You want to find a breeder that health tests for more than just your basic hips/eyes, ect and has the paperwork to back it up.
There are a couple of breeders here on this forum that may be able to point you in the right direction. BUt essentially you wan someone who knows what the breed is prone to and breeds away from that. Also, someone who knows what the standard is and keeps to that breed standard. And like I said before, you'll want a breeder who doesn't breed for quantity but for quality. To find a healthy puppy you may have to wait as those breeders take their jobs very seriously.
Furthermore, you'll want to find someone who is open to speaking with you about anything
Hope that helps!
Welcome to the forum by the way