Can I buy a museum pass for the year? Does that allow me to bring a guest into the museum

Yes, there are options for just that, if you plann to go 3+ times, i think the pass pays for it self. Enjoy!

There are different pass levels. There's a budget level community pass that pays for itself in 2 visits but has restrictions like can't go on holidays

Yep! You can pay in full or a small down payment with subsequent monthly installments. Many options to suit exactly how many people you plan on going with.