If the jocky pulleys are designed work well with modern derailleurs and 10 speed chain I'm guessing that the width at the teeth is a bit more narrow. The rest of the pulley is likely "standard", whatever that might be. But if the teeth are a little narrow you may find that the derailleur has a bit more effective float in total. That being the normal float back and forth on the pivot pins as well as the chain being able to float a little more on the rollers because of the narrower jockey teeth.
As for the 7 speed setup in the back if you're willing to mess around with the spacer, cone and locknut variations with the rear you can work it so the small cog is very close to the dropout with just barely enough room for the chain to slip on and off during shifts. WIth that setup you've got the hub as far over as possible. Then use a spacer combo for the other side to fit the dropouts. Now adjust the wheel dish to fit. If the dish turns out to be TOO extreme then the idea failed. But hey, at least you tried. The key would be knowing how flat can the drive side spoke "cone" go before it becomes too easy to flop over center and taco it's heart out. THAT is one specification that I've never seen.
Kimmo's OCR stands for Off Center Rim. Some companies, I know Ritchey is one such, makes rims with eyelet holes offset to one side so that the rim can sit more to the drive side and allow the drive side spoke "cone" to have a more durable angle. Definetly something worth looking into for this build if you're keen on the 7 speed option.