Thanks for the advice regarding host vs open bar, lawn games, bartender tipping math, and all the other things I asked about.
We had a cloudy day (great for pictures) with occasional rain showers, but that cooled things down a bit, and the beautiful tent protected guests from the random downpour. We did end up using the lawn games (ladder ball, corn hole, hula hoops) when the weather cleared and they were a huge hit with the children, as well as some adults.
We went with a hosted bar, and that was absolutely the right call for our brunch reception. Seriously, we saved about $3K doing it that way!
We did not assign tables (even though I got massively flamed for this on another board.) People just found places to sit with old friends, and made some new ones, too. Really, if you don't want to assign seats, it will be okay.
We did not end up using the florist beads I bought. @Jen4948
(I think it was her) was right. The flowers were so gorgeous the beads just weren't necessary.
Things I would change: we had waayyy too much cake! I knew this would happen going in, but my daughter insisted on having several tiers, deconstructed, as well as a sheet cake. I ended up bringing one of the massive tiers home and serving it at church coffee hour the next day.
The pictures took forever. I have no idea how this could have been avoided, as the couple didn't want them done until after the ceremony. So they got to the reception about an hour and a half after it started. The planner handled it well by opening the hot buffet at the right time, even though the couple hadn't arrived. They were fine with it and of course, there was plenty of food.
They had a fiddler and Celtic harp, which made some very danceable music. Only no one really wanted to dance. My daughter and her H didn't really care, and no one else did either, but if you want dancing to music like this, you do need a caller. (I would say I told them so, but I'm too diplomatic.)
The event staff told me this was one of the nicest receptions they'd done in a long time, because the guests were so gracious. (I think they meant no one got wasted or rude!)