The WL185 is a cardioid lav that is good for presentation and broadcast but it's not a theatre mic. It's not small enough to tape on a face or forehead. I also typically recommend omni lavs unless you have a really good reason to use cardioid.
Ear-worn mics are much easier for schools to use than lavs - I would recommend the Shure MX153 if you have to go cheap and the Countryman E6 if you have a bit more to spend.
I'd also try to get the digital QLXD over the ULXS if you possibly can. It costs more but has a major jump in feature set, and there are more frequency bands, including VHF, that helps future-proof you purchase against additional spectrum changes.
I agree on trying to get the QLXD, I just added 6 to my system, I have 10 of the old ULX line, the QLXD is great if you are in a busy rf area, I buy all of my headset mics from bodymics.com, I have High School age users...if one breaks, only $80 loss, or 20 ish if its just the cable....
+1 for the above posts. The Shure lav mics (183-5) are not theatre-based mics. Can you use them? Sure. The results will be less than ideal, and you'll probably struggle with feedback issues if poorly deployed and find them impossible to hide in costumes. Invest in some omni lavs that are inline and not clip-ons. You can easily turn a B3 into a "headset" mic by looping it over the ear and using some medical tape.