I have a few suggestions. I am new to civilian climbing, but have some military experience. As such my suggestions tend toward simple, inexpensive solutions.
First of all, great you bought Connellys book. It can put everyone in your group on "one sheet of music" regarding techniques, procedures, and gear choices.
My climbing situations are similar to yours, class 3 with exposure, with inexperienced companions (even more inexperienced than me..scary..). I take:
One "swiss seat" (rope harnesses) per person
One locking biner per person
One helmet per peson
Possible Class 4:
A few tied* 120cm runners
A couple 6mm(or thicker) x 20 foot tied* cordeletes
A couple quickdraws and pieces of pro
A few locking biners
Two rappel rings for anchors.
*tied runners or cordage can be untied and combined, or shortened as necessary; made into harnesses, chest harnesses, prussiks, etc.. Only carry the nylon type.
I do not use any type of belay or rappel device as the munter or super munter is free, weightless, always available and can not be dropped or lost.
Any time my group ropes up, we put on helmets. That helmet should be EN1078, CPSC, and ASTM 2040 compliant. Here's one for 18 bucks.
You might decide to carry a half or twin rope instead of a single, but consider the liability consequences. You mentioned bringing a Beal Rando. The manufacturer says it is good for a factor 0.8, 80kg fall, and that is exactly what I carry for that possibility, but if more than factor 0.8 is possible, bring a single, or double up that twin. To do otherwise with inexperienced partners who trust you is irresponsible, IMO.
A more experienced group might decide to use a half(not a twin) as a single; which is what Connelly recommends, and what I do with my instructor. Halfs are tested for falls on one strand (because they assume the other will pick up the load), twins are not. UIAA warns against this usage, however.
Here's the rope I carry, depending on the situation:
Lightest twin rope: Beal Rando (i.e. Ice Twin), 37g/m
Lightest double(half) rope: Beal Ice Line, 42g/m
My single rope: Blue Water II Plus
If your hiking companions do not know anything about mountaineering, but do not want to buy the previously mentioned book, here is a great free introduction:
If you want to try making the "swiss seat" out of rope or webbing, instruction starts on page 15. This was my only harness for years in the military. Use single rope; webbing folds and is painful. Of course, the BD Apline harness is better, but single use. A rope harness can be untied and used for many other things.
I could go on and on; after reading Connellys book please tell us all what you decide to take?
Hope this helped.