For your students, most comprehensive subwoofer design freely available is "
Thor", a Siegfried Linkwitz design
For a driver choice look at T/S parameters and S.L. analysis "
SPL Limits"
Originally, Peerless 830500 driver was used in Thor, if you can find it (at least it's in production again, AFAIK), it's best. All others are similar but some of it can't fit compression subwoofer, or can fit with some corrections in design, that probably won't be a problem for your students, especially because S.L. pages describe design process in detail.
FYI drivers with similar construction today make
Tymphany (under Peerless brand) AND
Scan-Speak (they are now different companies)
Also, there are smaller design, describing
Pluto+subwoofer, and it's also can be very informative and useful.
From my experience, Hypex modules work well with both XLS and XXLS type of drivers, regardless of their region with pretty small impedance
regards,
Boggy