You should probably pick all your finishes at once, so that you don't paint yourself into a corner by the step approach -- for example, to keep contrast with your floors via *stain*, I think you'd have to go pretty dark, but that will constrain your options for the other finishes later. I agree that painting them white or maybe a pale gray could be a better choice. But it helps to know what kind of look you're likely to want for, e.g., your new counters.

Think about what you are drawn to when you look at kitchen pics - not what you see pushed on HGTV. Many shows on HGTV are reruns and sometimes show ideas no longer trending in most of the new design pics I am seeing. Trends change so fast, that by the time you complete your change over in stages, you could have a kitchen which is no longer in style - which doesn't matter if you love the look you have chosen - so be sure you love the look.

If you truly love the white / gray current trend, then I agree to paint cabinets white, unless you like the (in my opinion drab) dark brown / gray look. White cabinets will be more flexible to style changes.

A neighbor of mine does have new dark cabinets and they are very attractive, but she did not use any gray, but instead cream to keep her kitchen light because dark cabinets can suck all the light out of a kitchen if not carefully balanced with other lighter colors. If you darken the cabinets, you will have black appliances, dark countertop and backsplash with gray walls - not sounding very light and airy.

For your first stage, consider changing out appliances and lightening the wall color. The warm wood tone will not look great with a cool gray, but would do OK with a barely there gray or light warm gray (which usually reads more greige or green). Neutralizing out the melon wall color and black appliances will allow you to assess your kitchen again without the distraction of the black and melon colors. While changing out appliances, consider a pretty stainless hood and either a countertop microwave or retrofit a cabinet by the fridge with the microwave if possible.

Then think about your cabinet color. There is a movement back towards warmer toned natural wood - I saw it in our local Parade of Homes. You might want to wait and see between renovation stages what the new design pics show and if you will want to move in the direction of working with the warmer tones, or if you have your own vision and want to go with it.

It can be tricky to do countertop and backsplash before cabinet color. What looks good on white cabinets might not look great on dark. However, there are some combos I've seen on both. I personally would be a little distracted by the backsplash, but that is the last thing to get changed in a kitchen refresh. You might look into the cost of removing it and repairing the drywall and just painting the area until you get to the point of installing a new one.

If you like the more country / farmhouse look, you might be interested in the Kohler Whitehaven cast iron or Kohler Vault stainless steel "short apron" farm sinks. The "short apron" style can be installed on a standard sink base cabinet. Here it is in my vintage kitchen - also I have seen my countertop on both dark, white and natural wood cabinets - it is an example of one which is flexible in that way.

[https://www.houzz.com/photos/my-pics-work-in-progress-phvw-vp~93784356[(https://www.houzz.com/photos/my-pics-work-in-progress-phvw-vp~93784356)

I don't think you would want to go to the expense of sanding the cabinets down and refinishing them. It would be cheaper to buy new cabinets. The gel stains That you see done are more like a translucent paint than an actual wood stain They obscure the grain. You might as well paint them, and a nice paint color would probably look better than a dark color as well.

What I'm trying to say is that you really need to consult a good local Kitchen Designer about your project first. I think that you have a lot more to consider here than you think you do. The decisions are all interdependent, and have to be made all at once so that it all eventually works out. For instance, gray would not look that great with your current floor and dark cabinets unless it were a very warm gray. Then, you'd need a lot of extra lighting in the room.