EJ water pumps routinely last 200,000+ miles and catastrophic failure is nearly unheard of, it's so rare i wouldn't believe it's an actual failure of an OEM factory installed pump unless I saw it myself. No need to replace.
Belt, pulleys, and tensioner I'd definitely replace.
The belt and tensioner are a given.
The toothed pulleys almost always need replaced - they're simply devoid of grease.
The others are questionable, i like to replace them but I can understand a dealer not wanting to charge that extra labor/parts.
I like to do the cam seals and reseal the oil pump (tigthen backing plate screws, crank seal, reseal pump body).
The parts costs are like $20, cheap and easy. But a dealer would charge two extra hours of labor probably - so $200-ish.
Drive belts - why not just do it all and be done with it?
That said - they're cheap, easy to replace and can be inspected or done later, not a big deal. They rarely cause issues - though it's possible for them to fail and interact with the timing belt, that's rare though.
If yours has the plastic drive belt pulley - i'd replace that as well. I forget when they used those.
I was on the highway in November when the belt went, due to a frozen tensioner/idler pulley. 2012 3.6 with, yes, 105,000 on it. The local Subaru dealer replaced the belt and the tensioner/idler pulley (but did not replace the water pump) for under $225
That's a different issue, those pulley bearings (2 of them) should be replaced every 60,000 miles or so. 100k at the most.
Those fail due to the idler pulley bearings loosing grease (same thing that happens to timing pulleys).
The bearings are $10 and take 30 minutes to tap in, super easy job. I do it every 60k or so.
That's a well documented issue and specific to EZ engines only, lots of information and stickies about it and the options you have to repair.