Howdy, I work in Morgantown, but there are quiet a few of those...lol
Just to make sure - you realize that if the belt breaks those engines usually bend lots of valves and you're into major engine work? That's one reason this is important. I've bought Subarus (very cheap) with that engine with "new" timing components that were broken and had bent valves. So these recommendations aren't just archaic, old school, uncle bob, I heard it from my neighbor stories.
I'd install new Subaru belt, timing belt idlers, tensioner, water pump. Done.
If you want to be cost effective - install a new Subaru belt and cogged pulley ($100 for both). Those are the most common failure items by light years. Check the tensioner while it's apart, if the hydraulic seal is wet (leaking), replace it.
You can avoid the water pump - if you're doing this work yourself they're not hard to do at all, they don't fail often, and they just leak. It's not going to strand you, it'll give a warning when you notice drips/smoke/low coolant, not a big deal if you pay attention. I'd leave the original water pump before I'd install an aftermarket one.
If you do go with a lower cost option - particularly if you're using aftermarket parts - consider checking the components after 2 years or 50,000 miles. I wouldn't expect 100k from them, but then again, if they do fail they seemingly fail at random mileages, not just early.