Does this Hy-Vee have a conference room where a small group of people could meet for a short meeting?

Yes it has a room in the back

Yes! As you walk in the front enterance, there is a flight of stairs (as well as an elevator) on your right. The meeting room is on the second level. Lots of windows so you don't feel like you're in a box, which is nice.

Dining area

Yes it has a dining area that would be appropriate for meetings.

Yes it does upstairs

Yes