1. All other things equal, I’d go for single storey
2. You hit the sweet spot actually. That said, even a 2100 sq ft would be ok but then the house and corresponding PITI will be bigger and home may negative CF even more
3. Too many to list, depends on where you buy and what kind of upgrades you choose (or the home comes with). Example - in my last 2 purchases, I chose tile and/or wooden for all except bedrooms (which were carpeted). Make sure home has all working appliances and fridge. Allow pets!
4. I hate to spell out the obvious but competitive rent, even it means you negative CF if finding a tenant asap is your goal. the rental market is great in Austin at the mo but is also equally cut throat as well.
I’m sure you know this already but a lot of builders aren’t selling to investors. That said, there a few - just make sure your realtor is on it.
Good luck on your search and let us know if you need anything. This is a great forum. specifically, neil Narayan, this forum’s legend has been very helpful.