Yes,yes,and yes.

You'll want a good lock(http://www.missinglink.org/Pages/bike_locking.html for info). Front and rear lights are a must at night. Full fenders will keep things much cleaner in bad weather. A bell is helpful when interacting with peds. You'll want to carry a multitool,patch kit/levers/pump(the Topeak Morphs are the ish),maybe a spare tube,and something to clean up with(babywipes,or paper towels and small bottle of hand cleaner). Given the style of bike,the factory rack will prolly fit best. Any bag can be bungeed to the back. If you get panniers,make sure they have proper click latches and not just hooks. In the future,you may want to go with thinner tires for more speed and/or get some that are puncture resistant Reflective sidewalls are also nice. And you may wind up changing the bars and seat to dial in your riding position/comfort and maybe adding barends for more hand positions.

All good suggestions.

I really don't know anything about trunk bags either, except that I've seen them around from time to time.

With a Townie there's no weight on your hands. One thing I do to get some weight on my arms and give me a more relaxed ride than the straight up riding position, is to lean forward resting my forearms on the grips and just let my hands dangle in front.

Also, being a very stable bike, it's easy to ride with no hands. You can ride and flap your arms, pretending to be a pelican.:D