My general approach to leashes is that "if you pull, I stand still". Clever dogs get the idea pretty quickly

For two, I'd get the basics - ie, don't pull - with each on its own first, then try the two together. If they'll behave, one of the splitter leads would make things easier for you at the Fair, as you only need one hand

If the dog sits down and won't follow on the leash, I use 'pressure-and-release', as I would training a pony or calf to a halter. I've written it - and lead-training, too - up several times, you'll find it / them if you search.
Good luck!