The thing about setting your system on a curb which then sets over your duct coming out from the roof top is that The duct has to be matched up. Normally on retrofits this can not be accomplished easily. So this is why the duct will come out the back then 90 down. It is much easier of an install and sometimes it is the only way for the install to be done. I do have a preferred list of manufactures, but it is based on failure rates of evaporator coils, noise issues and just over all sturdiness of the system. I also look at the distributor who sells the equipment to us the dealer and how they take care of me so I can take care of you the customer. Plus I'm smart enough to know that warranties are limited warranties and sometimes created to sell lesser made systems. So every area can and probably is different when it comes to brand.

Yes, install a new 120V circuit for the range. Whether it's 15A or 20A will depend on the requirements of the range. I'd leave the 240V circuit in place and remove the fuse as you suggested.

I'm guessing in the 1990s whatever preceded GardenWeb was full of posts advising people to hold onto their mid-70s washers and dryers because the (then-)new stuff was junk. Not disputing that it's true, but the sentiment is right up there with every generation thinking the young kids are going to ^#*& compared to when they were kids. All that said, I would run with the electric dryer until it's beyond economic repair. A new gas dryer of any decent quality will run you several hundred dollars. Add in the costs of running the gas line to the laundry room (and of making sure there's a 120 V socket available for the gas dryer; it won't run on 240), and the lower cost of gas drying will take a very long time to make up for what you've already paid to get the dryer. Who knows what gas costs/electric costs/your living situation will be by the time the payback arrives?

"So a 200A service should be OK with an induction cooktop unless a lot of current is already allocated to big power dissipators such as electric heating, a heated driveway, electrically heated high air flow MUA, or a Tesla." Yeah, they may be fine w/ 200 and may not be. It depends on what electric devices they have or will have in the future, how they use them and what their current service entrance is. They can stick an IotaWatt or similar on their service to get an idea of current usage - both peak amp draw and voltage drops (pushing the limit of the service entrance/xformer can cause voltage drops that can quickly damage electronics). It's important to account for seasonal variation though and to understand the limits of their service entrance and how close the new induction will come to stressing it. Also, very likely everyone will need the ability to charge their cars at home and it may be less expensive for the OP to do that upgrade now along w/ induction rather than later. My primary car has been electric for 7 years and my truck will be in the next year or two so we'll have two cars and a truck to charge. The benefits are too massive to ever go back to petrol (and financially it's rather dumb to buy a new petrol car today).