DO NOT TILL is the majority theory around here. When tilling, like you said, you bring up weed seeds. Also, because tilling is not an accurate delicate process, you end up with different depths, and when the soil actually settles, it will be rough and bumpy.

Just scratch it up with a rake and seed.

How about rolling? Do I need to rent a roller, can I just step on it to make good contact, or should I just leave it alone?

Topdressing will give equal if not better results. No more than 1/4" of topdressing over the seed. Dry peat moss makes a good inexpensive topdressing. Easy to spread with a dustpan. Double down and roll before topdressing.

Yes you can just step on it.

Bad advise around here. Not sure where the 'consensus' about NOT tilling came from, but is not true. Tilling a yard prior to planting has many advantages/benefits - I'll name a few:

1.- Can add lime (per soil test) at the time of tilling
2.- breakup the hard soil to make a fluffy seed bed for the roots to penetrate the soil deep.
3.- add organic matter or topsoil (weed free)
4.- dramatically improve drought tolerance, short and long term.
5.- chance to level your yard if have depressions, divots, etc.
6.- opportunity to remove construction debris, stones, boulders, rocks, etc. Even left over concrete from when the house was built.

Yes you will have weeds (winter weeds) but nothing long term or almost nothing a post emergent herbicide can't kill.

Even if you have irrigation, tilling still VERY beneficial.

There several university research on this around the country that supports the above statement.

To the OP, in your case because you were growing annuals in that section of the yard, you should not need to till that area in order to grow nice grass in there.

With few exceptions, the costs and effort expended tilling are going to outweigh any advantages.
By all means till if you can: Forget the cost of buying, renting or highering the proper equipment ( a tractor or similar, a 3pt hitch tiller that will hold consistent till depth, a box blade, a rock hound, a roller, landscape rakes, etc.) Forget the problems that arise if the soil has significant clay content. Forget the effort spent on removing any debree brought up. Forget the weed seed that is brought to the surface. Forget the time spent regrading for drainage. Forget the time leveling and smoothing the surface. Forget the time it takes the soil to settle over a period of sometimes years. Forget the addition of soil to fill low spots and reestablishing drainage as the soil settles over time and the reseeding of that new soil. Forget that there are more effortless and cost effective methods that produce as good, if not superior, results.
Most important of all, forget tilling.

err.... hiring.