I was hoping that the statements would provide interesting discussion points in addition to personality discrimination.

Probably will the former, but I'd absolutely get rid of #2 and #4 - politics is the mindkiller, and it's no accident that etiquette manuals proscribe politics during polite discussions.

Divide the groups in two based on familial affiliation (they'll expect that).

Ask the following questions:

1. My radius of "personal space" is... (tiny/small/medium/large/immense)
2. I am... (short/somewhat short/average/somewhat tall/tall)

Bias x by (1) [near aisle should be "tiny"] and y by (2) [back should be "tall"]. Average groups, ignore children.

Is the farmer/forager distinction very well supported? (And I don't mean some random musings on Robin's blog.) And have these statements been validated for the distinction?

I didn't see any google results for conversation compatibility, so I suspect that you could just make your own - it doesn't have to be perfect at all. Possible categories of conversations you could encourage could be things like books, music, food, relation to the new bride and groom (congrats mosb), human psychology, or travel.

Here's my current proposed list of statements for people to (strongly) agree/disagree with -- no neutrality allowed. The idea is to identify people on a farmer/forager axis, and then to cluster people according to similarity (subject to other constraints).

1. If there were cheap, tasteless, food pills that gave you all the sustenance you need, I would barely eat other food.
2. I believe it's everyone's duty to vote.
3. I regularly exercise when I should be working.
4. I think governmental oversight unnecessarily slows down the progress of science.
5. My clothes are definitely more about style than comfort.
6. I believe that travel is over-rated.

Is it an academic exercise, or are you planning a real wedding reception party?