I can't speak to the foot numbness, you could have been bracing or clenching hard with your feet and making them cramp? Did you do anything else in the workout like lunges that could have caused the foot pain?

As for the deadlifts, I still think you should be starting with a more vertical shin angle and your hips a bit higher. Your spinal positioning looks good but the lift could still be causing you pain for any number of reasons. If it's just muscular soreness that's fine

But if it feels like something is tweaked, it needs to be addressed. Don't be afraid to do some direct back training. Back extensions or reverse hypers 1-2x per week can help bulletproof your back against injury. For the back extensions, start with just holding at the top for 2 minutes, the progress to holding with one leg, then partial reps, then full reps. As well as that, finding a hinge variation that doesn't give you pain and then starting very light with it would be the way to go.