You need to take them to a competent repairer to get any leaks fixed. The pads will probably have dried out and warped, and the joints will need to be recorked or rewound with thread.

Start with a soft reed, like a no.1, and read a general book on clarinet technique.

Orchestral clarinets aren't in handy keys for most British Isles folk music. If one of the instruments is in A, focus on that one. If they're both in B flat you won't be playing alongside fiddlers any time soon.