There is no simple answer to this question. Nobody makes the best of everything at a given price point. If there was one universal best manufacturer you would know about them already and not need to come on a forum and ask. The best strategy is to get appliances from different manufacturers that are well regarded in each category. Do some reading of past posts on this forum because there has been a great deal of discussion about each item on your list. Then if you have more specific questions after doing that, come back here and ask them.

I'm a fan of convection ovens, if you can fit them in your budget there's no reason to avoid them. You can always turn off the convection if you want.

There is a lot of variation in appliances, and most have quirks. There isn't a this is good quality/that is bad, except for a very few. Your best bet to start with is to go to all the independent appliance showrooms near where you live and talk to the sales help. If you get someone who seems clueless, ask nicely if they have someone who knows more who can help you. Look at the measurements and prices, and check out the lists of features. Then go home and check out the ones that looked appealing on the makers' websites. Download the manuals and see what the features are, and check the reviews. When you have it narrowed down to a few choices for each, come ask about them and let the members talk through your choices with you.

Recommendations: These may cost a bit more, but you should check out induction cooktops. They're also electric but don't have the pitfalls that standard glass electric stoves do (hard to clean, poor control, etc.). You do need to use iron or steel (inc. clad) cookware that is of sufficient quality to react with the induction, but it's far superior. Most people like it better than gas, too.

A convection oven is a good thing so long as you can turn the convection off if you need to. The way modern ovens are made, they don't necessarily heat evenly. Convection helps make up for that. What you should look for is "true convection", "heated convection" or "European convection". Some ovens just have a fan added to a regular oven, which isn't all that useful. The three terms above, generally, all refer to an arrangement where the air the fan moves is heated by an extra element. "Natural convection" is usually used to mean use of top and bottom heat to make the air move around without a fan. A couple of very high end ovens have a curved ceiling to create natural convection as well.

Every new oven takes some getting used to. Your times and temperatures will inevitably be different to what you're used to. Adding convection means that it's just a bit of a bigger transition. For items that cook in under an hour, the rule of thumb is to try 25 degrees less or 10-20 minutes less with convection. It's just a matter of getting to know the oven. Once you get used to the oven, you'll get an instinct for which recipes need changing a little and how. Newer recipes often assume convection.

I'm not sure what you meant by microwave convection oven combo. If you mean a single unit, that's not the best idea if it's your only oven. In that case, or when you read about speed or steam ovens with convection, that means hot air convection fans only, and not a regular bake or broil element. (Some of the speed and steam ovens now have modest broil elements, but I've never heard of a convection microwave that does.) There are also units that are a single item with an oven and a microwave, or those plus a warming drawer. When one breaks beyond repair, you have to replace the whole thing, and often, when it breaks, you can't use any part. Perhaps you just meant you were going to do a MW over an oven. That's fine. If you want to save some money, instead of getting a built-in to match your oven, you could get a freestanding Sharp or Panasonic (they make most of the microwaves that the other makers sell anyway), and trim it out so that it looks nice with your oven.

When you're looking at dishwashers, bring a couple of your bigger items (clean) to try them on for size. One of your dinner plates, your everyday big pot that you want to go in, cereal bowls, etc. My DW, for instance, doesn't fit more than a few cereal bowls well, but we use more rimmed soups, which fit better. Miele, at all feature levels, seems to be the best loved dishwasher.

In a fridge, the most repair prone part is an ice maker, and even more so if it's through the door. Through the door also takes up a lot of space. If you'll use it a lot, get it, but don't assume that you have to if it's not going to get enough use to be worth it. With a French door, make sure you have plenty of room on either side for the doors to open. You can choose among the brands to have a lot of freezer space that you have to bend far into to get to the bottom, a shallower easier freezer that doesn't hold as much, a two exterior drawers freezer for more space but easier access, or two/three drawers where the top drawer is flexible temperature and can go fridge or freezer. Check the interior layout and make sure the shelves and dividers work for you. Make sure you're comfortable reaching the top shelves of the fridge. Also, make sure the doors open and close easily.

Fridge capacity is measured in cubic feet, which is fine for seeing if a couple of different styles are similar sizes, but doesn't actually translate into space you can easily use. If you want to compare usable fridge capacity bring a bunch of containers, bottles, etc. and fill 'em up. If you're into gallon milk jugs, tall bottles of wine and other hard to fit objects, make sure they'll fit.

I won't say a lot about hoods. There are some experts here. In general, I think most people are happy with 600 cfm power on their fans. Many are rated more in the 400 range, and might be adequate for you, but in general a stronger hood on a slower setting does a better job than a lesser one on a higher setting. Search the threads for more info there.

Good luck with your shopping. If you keep looking and imagining yourself cooking and using them, and reading about them, you'll start to get a feel for which ones you want for yourselves.

I have a GE dual fuel range. The top is gas and the oven is electric and convection. I've had no problems with it for 10 years now. I have never had a problem with GE ovens. I just bought a Kitchenaid Architect II Series french door refrigerator with the exterior draw. I've only had it a week, so the jury is still out. So far I love it. I bought a 5 year extended warranty for $250 because no matter what brand I read about, they all have some problem or another so at least I won't have to pay for a repair.

I will also warn you about stainless steel appliances. I decided against them when I started reading reviews that they are rusting. I googled "rusting stainless steel appliances" and it seems every brand has this problem. It may not happen to everyone who bought ss, but I didn't want to be in the small percentage that rusts. One person mentioned that nickel went up in price so they are not using the same amounts of chromium vs nickel and that may be causing the problem. I don't know how true that is, but I preferred not to take the chance. The manufacturer will not do anything about it because they consider it cosmetic. A common complaint is that they smear very easily too. I decided to buy black and it looks great.

Hope this helps with your decision.