Lot's of good advice here for Honda's. I think you're on the right track with everything you're doing, but I have a few more recommendations that I've learned the hard way after 5 races on our Honda.
Since you're already going in the engine (good plan) check the bores and the bearings. You can pick up a ball hone for <$40 and give them some new cross hatching if they need it. Just do your homework to make sure to get the right diameter and grit. A fresh hone will work well with your new rings.
If the bearings look a little rough just replace them all, they're not expensive.
Have the block and head checked for flatness, again pretty cheap and worth it.
Lapping the valves really is worth it.
Like somebody said above, buy the headstuds now. Yes they're $150, but they are a must for your car to reliable. And don't buy the cheapest headgasket Rock Auto has, buy a good name brand one you trust. Ask me how I know...
Get a largest stock radiator you can if your car came with different engine options. We have a VTEC radiator in our car even though our engine is non-VTEC. The VTEC one is thicker so it adds some cooling capacity.
Also do yourself a favor and clean the engine and trans before putting it back in. The judges aren't going to care if your stock engine has all the oil and crime cleaned off of it. It makes working on the thing 1000x nicer.
Make sure your teammates truly understand how much this costs. The hardest part about Lemons is finding good teammates. Your best friend may not be the best teammate People see $500 race car and think it's going to end up costing a few hundred bucks to go racing. Building a car from scratch will cost you anywhere from a couple to several thousand dollars. Then there is the safety gear, driver conform (gauges, cool-suit, radios, etc.), good brake pads, tires, towing the car to the event, entry fees (~$300 each driver) and so on. Once your at the event there is lodging, food, and several hundred dollars in fuel if you run the whole weekend. And once the weekend is over you have lots of maintenance to do on it. We spend a few hundred bucks bringing the car back up to tip top shape between races.
That being said, it's worth every penny! Good luck and hope to see you at Gman!
One last thing, do the theme last if you have time. It's not a big deal if you show up to your first race without a theme because you spent your time and money prepping the car!
CLUB 991 - Honda Prelude
Gingerman Oct. 2018 - We Got Screwed
CMP April 2019 - Most Heroic Fix
Gingerman Oct. 2019 - Class B Winner