JR Pass - Hokkaido

Hi, we are a couple, travelling to hokkaido this christmas. we would be landing in New Chitose Airport and then immediately travelling to hakodate for a night stay, then travel to sapporo. but we will be making day trips to Niseko and also Otaru and maybe Asahiyama.

please advise which JR pass we should get that can allow us to travel to all these places without any hassle.

appreciate very much as we are both extremely confused over all the different trains and rails and all the networks and systems.

very lost here!

thank you for your help!!