Bruce is a handsome fellow! Difficult to say anything about his weight from these (very good) photos, though. One would need to see him from above. As @Cbrugs says, the waistline should be visible right behind his ribcage.
The breed standard for English bulldogs is 25 kg so with that in mind...
Is it the cutting or just the fact that someone touches his feet that is the problem? If it is the cutting, perhaps a dremel would be better? And don't try to do all nails at once. I would try that at home before trying to lift him up in a sling at the vet if he gets agitated.
Good to hear your boy is ok, and hopefully you and your dad too. It is really scary to see your dog being attacked like that, but as others have said, report to the police and if the other dog's owner si to be found, make sure they (or their insurance company) pays for any costs you have.
No, Fromm isn't available here. Our Castor did better on Acana than on Orijen - it seemed like Orijen was a bit too "rich" for his tummy. But all dogs are different so what suits one tummy might not work for another one!
Orijen is good, as is Acana. Have you tried to soak the kibble? Pour hot water (boiled, not hot from tap!) over the kibble and then wait until it has cooled down (do not feed hot food!).
It often takes a week to transition from one food to another.
Best of luck - seems like your Agnes has come to a great home! It's probably a good thing that she has a dog friend to play with but as you teach her to play, I would not go for anything resembling tug-of-war.
Have you tried big balls? My Castor liked any old basket / soccer ball and there is...