I'd suggest get the CL level up with bleach, maybe @ shock level, and keep it there till the equipment is running. This'll help stop serious algae issues while you're getting the equipment fixed.
Yep hold off on the 'pool school' till the equipment is all together.
Good luck finding the clamp... Don't give up on finding the service co. and hassling them, you have before & after pics to show they misplaced it. You might be able to get the real estate co. to bring pressure on them. The real estate co. hired them to take care of the pool, which they did not! Failing that, it might be worth while to call around some local shops, they may have a stash of parts.
The pooldevil skimmer is awesome, I highly recommend. I own one and plan on gettging a 2nd for the leaf-in-the-pool season this fall.
The pool cleaner you have the link for has good recommendations. I persoally own a suction-side (plugs into skimmer) vac, and plan to get the pressure-side model this fall when they go on sale. Any suction-side cleaner puts the gunk through your piping and into pump basket. Not so good for me, I get twigs, acorn etc, scared of something gettign jammed int he pipework. Pressure side has it's own bag.