Mrs. Carey,
The BMS School Rocket (highly recommended!) is $5.25 a kit. (Pick "School Rocket" off of
this web page) It is complicated enough to be interesting (and teach some basic rocket-building skills) but still easy to build. It is rugged and handles wind well. For $1 more each they can be equipped with payload sections that are big enough to fly small electronic altimeters in.
In looking at what you have selected....my first thought is WOW, whoever Sargent-Welch is, they're sticking it to you. Look at
https://www.acsupplyco.com/estes/bulk.htm. They work with schools all the time and will save you MUCH over those prices.
For the Electron Beams/Porta Pads: you could save serious money if you just went to Michaels Crafts (I see three stores in Tulsa) and picked up a couple of Estes Taser launch sets. Each will have a Porta Pad and Electron Beam in the package - and the packages are $20 each - or less if you have one of their regular coupons. This, of course, depends on those particular stores having rocketry stuff. Not all Michael's stores do. That's compared to $130+ for your Sargent-Welch list for the same things without the Taser kits!! Better to put the other $90 into more motors.
The Taser's not a bad little rocket, but requires three different kinds of glue to put together right, which is kind of a pain.
I see there are two Hobby Lobby stores in Tulsa as well....another possibility.
Next - how big is your launch site? B6-4s will put Alphas (and even the heavier part-plastic Alpha IIIs) pretty high. If your launch site is really the paved area in your little picture, I'd suggest sticking with the Alpha IIIs.
If you have grass or dirt and don't mind going to two sources, I'd go back to my original recommendation of BMS School Rockets. They're about the same size as Alphas (a little taller) and recover on streamers, so don't drift as far as an Alpha/Alpha III would.
Another good choice (and a good flyer) if you want the plastic nose cone/plastic fin set like the Alpha III is the Generic E2X. This one is only available as a bulk pack.
Actually, School Rockets do hold up to landings on pavement - I've done it inadvertently a couple of times - but fins likely will need repair.
I could go on and on....
One more bit of advice: whatever rocket you choose - get one or two for yourself and build one (and preferably fly it, too) before going before a group of kids with it. You'll be much better equipped to help the kids with 'em then.
Good luck!! (but get another vendor - that one is taking you or your school to the cleaners!)