Well, I think the problem here is that you are expecting $20 per person for food, tax, tip, and drinks. Which means you probably can’t have alcohol unless you have a cash bar, and you must find a place that can do a plate of dinner for about $10-12pp.
That is going to be quite challenging, but NOT impossible. Now, let me ask you this-
Where is your rehearsal going to be? At a house of worship? Did you think about maybe having catering brought in for a picnic buffet? I know of some LA-based italian restaurants that do catering and could easily feed 50 people for under $500 for everything, but you won’t have a restaurant with tables and chairs. I’m sure there are mom and pops near you that can offer the same.
What about hiring a food truck and bring dessert (if it’s in a warm month, Joe’s Italian Ice might be fun!)? Like, the goumet mac n cheese truck or grilled cheese truck? It would be very different, memorable, and perhaps affordable. They usually require about $1000 minimum food, so it would be over budget, but it would be fun, unique, and not cost much more to add dessert and drinks.
Here’s another question-
Can you instead have a dessert reception? If you plan your rehearsal for say, 730pm with your venue, then you can make your rehearsal invitation “join us for a dessert reception afterwards” and include a sheet that has a few nearby restaurants that folks can go to before. $12 will get each person a nice dessert and one alcoholic drink plus tax, tip, and group service charge.
Otherwise, you’ll need to do some research on your own. But with 50 people and only $1000, you can only pick a restaurant where dishes are $10-12, and even that might be too high.
Try to find a non-chain, something local. The chains all have prices that for food alone, you’re looking at $15+, which doesn’t fit your budget. You’ll want to drive around your venue and look for small mom and pops that are big enough that you can fit, but since you are spending so little for what I assume is going to be a friday or saturday (ie peak), they can still have regular customers throughout the night.
Just some thoughts and ideas.