Elibean good point about him jumping at DC's - don't want that!
It is excellent that you can recall him just before the chase - keep an eye on that and always jump in before and you are halfway there.
If he does go off on a chase do not recall him. When you see him coming back to you (eventually) start to call him and give him a great treat and make a fuss of him (even though you are feeling grumpy and fed up) The coming back to you MUST always be the best thing ever.
IF he does catch something and has it in his mouth, totally ignore him, do not call him, do not try to get it off him. He will not want to give it up so don't even try however what he will learn is that you are not bothered and come back anyway. People that try to remove the prey from the dogs will just get dogs that stay out of reach and never get the dogs back.
I had a client with a lurcher who used to catch rabbits, he would come back with them in his mouth , the owner and I totally ignored him, he carried it for a while trotted alongside us, then got fed up put the rabbit down and it hopped away happily
They don't always hop away! If she had turned it into a chase game he would never return.
Re playing with other dogs - people often differ on this but I don't encourage mine to play a lot with other dogs. (I want all their good times to come from me, for various reasons, makes training easy and the bond stronger between my dogs and me). They can play a bit but I want it to be constructive play! I don't let my DC's run around screaming and yelling for the hell of it, and I don't encourage my dogs to do the same.
So chasing, running with other dogs is fine but when it gets to the bundling in and neck biting etc I will step in and stop it.
So when Mouse meets a dog, don't always let him play, sometimes walk on by, other times let his sniff and then call him and walk off with a great game or treat. You again need to watch his body language you will see his behaviour change before he gets too rough. It may be very subtle, he may slightly freeze, his ears will change position, he may go down into a bow, his tail may alter position, he may slightly turn away. When you recognise the signal, do a cheery recall and walk in the opposite direction.
Betsy yes you can teach old dogs new tricks - in a sense as he is a chaser you have a very strong chase drive you just need to redirect it. Don't stop it as it is such a stress reliever for dogs but direct it onto something that does not mind being chased. Give the book a try - start it on a long line. He may take a while to learn new behaviour but if you are as stubborn as him it can be done.