I've commuted and toured a little on a similar mountain bike, and as I'm sure you know, some of the bars you mentioned can be a bit pricey, especially if you are not sure if you will like them.
One direction that you can at least try, and very cheaply, is pick up some used risers with a slight back angle to the grip areas, these were very common on all kinds of hybrids and you'd be able to find some at a bike co-op for probably 10 bucks or less. The riser part will get the bars up a bit, and or you can change the stem also. I found the wrists angled back a bit too make a real difference. Add on some ergo style grips and bar ends and this also very much increases hand and wrist comfort. You can find inexpensive ergo grips but I'd strongly suggest ones that have those locking in place tightening bolts to keep the position just as you like (no twisting downwards)
Cheap bar ends work well too, you can also go to much better ergon brand grips which incorporates very ergonomic bar ends. All this stuff can make"mtn" bars a reasonable option.

Then there are butterfly trekking bars, you can find new ones for 20 bucks at nashbar, again you'll use existing brakes and shifters and with both these options, if your cables and housings are in good shape, you can just slide the old bar off and slide everything into new risers or a trekking bar.
Easy peasy and a cheap tryout.

Only you will know what you like, but I'd suggest trying these out before you spend 100 bucks on a bar or more, at least you'll see how diff setups work for you.
While you're at this, if suggest putting one of those adapters to be able to use face plate style stems, so much easier to change things.

A good bike store should have a "threaded" to "threadless" post thingee to be able to use stems with faceplates.