This will help with putting a value on them. Put "Snell Type A" in the search box and away you go. Be sure to look at the sold listings as well.
I have owned six pair of Type A speakers. They are one of the most realistic sounding speakers ever designed, in my opinion. I have owned Proac, b&w 802, Quad esl-63, Spendor and others, and just a month ago returned to the snells for my main system.
The electronic crossover is only needed if you want to separately amplify the bass module, which is not necessary. There is an internal crossover (a spectacular one tuned by Peter Snell... Don't let anyone mess with it or "improve" it unless it stops working) in each top module that separates frequencies so you run speaker cables to the inputs of the top.module and then short speaker cables from the "to woofer" outputs to the bottom module inputs. In the AII there should be additional outputs labeled for biamping and those must have a shorting plug inserted to use the speakers without the external crossover.
As far as value, if everything is working well and the cosmetics are good the resale value is typically in the $600-700 range. However these babies will crush most speakers under $5k retail, and many other under $10k. The midrange is absolutely amazing. They image like minimonitors due to the baffle design. Bass is seamless and the whole presentation is incredibly musical. Dynamics are among the best I have heard. I like them best with a warm tube amp.
The key thing about all Type A and AII is the woofer surrounds. If they have not been resurrounded it can be a real issue, because they are difficult to do correctly. The value of these speakers without surrounds intact is questionable, and all of these speakers required new surrounds because the original foam surrounds just did not last. Flip over one of the bottom modules, unscrew the bottom panel, and cross your fingers that the surrounds were redone. If Snell did the resurrounding they always wrote a date in the baffle next to the woofer. If the surrounds are redone you shouod be good if everything else works. You can examine the midrange surrounds by turning out all the lights in your room and shining a flashlight down from the top of the grille on the top module. Hopefully those are fine. But if not, Mids surrounds are easier for any competent pro to do.
If your woofer surrounds need a redo there one person in St. Louis who knows how to do them... Lloyd Faulkner. I think Carl at Carl's custom loudspeakers on the east coast may also do them. Let me know if you need more advice. You can remove the woofers and send just the woofers to them.