Originally Posted by Hondo6

Nice bikes.

Just pointed out the possible RD replacement requirement so the OP would know it might be required.

No argument re: Shimano RDs. Shimano 6-9 speed indexed RDs - and road 10-speed - all share the same actuation ratio (Dura Ace 6-8 speed excepted), so they should generally be interchangeable. (Dura Ace 6-8 speed will also reportedly work with non-Dura Ace shifters using alternate cable routing.) And as you note, they're readily available and anywhere from inexpensive to whoo boy! expensive.

Only possible issue I can see would be trying to use a very early SIS RD to shift 8-10 speed. Some of the earliest Shimano indexed RDs might not have enough lateral travel capability to shift the wider 8-10 speed cassettes. If I recall correctly, I've read accounts indicating that some do and some don't.

Existing FD might be a bit touchy as well. Brifters are indexed for front shifting also. I've read accounts of people making them work with older FDs. Haven't tried that yet personally, so I can't say how difficult that might be.

FWIW: new MicroShift 2x7 and 3x7 brifter sets are apparently still available. Unfortunately, they're also now about the same price as Shimano's Tourney brifters (between about $80 and $97 per set, plus tax and possibly shipping, Amazon or eBay).

There are also a similar line of brifters sold under the "MicroNew" brand that are generally significantly cheaper. However, with these caveat emptor may well be in order.

Elsewhere on Bike Forums, it's been posted that MicroShift says the MicroNew versions are unauthorized counterfeits of theirs. (Comparing the products' physical appearance and markings lend credence to this claim IMO.) The quality control also may not be as good. I personally would be hesitant to buy MicroNew for those reasons.