Refrigerators come in fairly predictable sizes. The most critical dimension for future planning is width. What have you got now? Is it adequate for your needs? Do you want wider or narrower? If you think you might like a counter depth 'fridge in the future, that might well need a wider opening than you currently have and you'll need to plan for that.

Ex: our old fridge fit in a 33" opening. There wasn't ever going to be more space for a 'fridge in our kitchen, so the new one also fits in that space. I say "fits in a 33" space" because the refrigerators themselves are all sorts of numbers just under 33" with the intent of fitting in that standard size opening. As long as we knew it had to fit in a 33" space, then there were lots of options.

Unless you're thinking of side-by-side independent 'fridge and freezer units, you'll most likely be looking at 33" or 36" widths. There are wider ones, but they aren't the most common. Once you get that far, there is some variation in height, but not so much, and there is a sort of "standard" height/height range that is pretty easy to work with. Go to an appliance website and check out the options in your desired width, so you can see what a likely height will be. Manufacturers aren't entirely brainless, they know that customers won't be buying their stuff if they only build their refrigerators to "unique" heights that don't match current cabinetry.

Stoves tend to be either 30" or 36". You really need to decide now what you'll want next in terms of size. Especially if you're doing a nice hood, you need to know if you'll make it 30" + 6" or 36" + 6". Otherwise, you'd have to add or subtract cabinetry down the road, which doesn't sound like a good plan.

Full sized refrigerators need a 36"W x 70"H alcove to fit in. That works with any standard consumer grade fridge on the market now or in the future. Most fridges are around 70" tall, so put in some molding or a filler at the top to cover that bit of gap so that it can be trimmed if needed. Buy an extra touch up kit for that too. The depth is more variable. I usually use deep refrigerator end panels, which in some lines are 34" deep that you can cut to size. I'd suggest making the depth around 30" and that will fit all but the deepest Samsungs. Or, choose to go counter depth and make the paneled sides 24".

Slide in ranges all need a 30" space between cabinets, but some, like the Electrolux induction unit need a bit more clearance at the front for the doors of the adjacent full overlay cabinets to clear. I might do a cabinet line that will do extended stiles here and plan on doing 3/4" extended stiles on each side. Then you'd just need an 1 1/2" filler somewhere else in the run to work out to 3" to keep to standard cabinet widths. If you do that, you want to make sure that you have the stone extend 3/4" over the side of the cabinets as well because the slide in needs that lip to rest the flanges on top of.

DW's are all 24", so you're good to go there.

If you are planning an additional wall oven as well as the range, then choose a 30" for it.