Just wanted to say what a fantastic kitchen. So pleased you're keeping it! Formica would be the period correct work surface and can still be bought but may not fit with your budget? I would also look at having a carpenter produce your cabinets. They can be cheaper than off the shelf and would be better build. To save some money you could buy cheap plain carcasses and have a carpenter make doors to match the existing ones that you can then paint. That's what i'd do!

The flooring company could check the moisture content to see if its ready for the new floor with a test meter. But if you're having solid wood worktops and if there is a lot of moisture then I wouldn't want to have these installed, also if you're new kitchen doors are solid timber these will also be affected by a damp atmosphere/high humidity. I think you really need to get some heating/dehumifier on before you start.

Unless you particularly like the desaturated look of all greys, my instinct would be to go with a more natural shade of oak for the flooring. https://www.howdens.com/joinery/floors/flooring/vinyl-flooring/quick-step-livyn-single-plank-natural-oak-luxury-vinyl-flooring-2105m-pack-sdh3680 Possibly even this; https://www.howdens.com/joinery/floors/flooring/vinyl-flooring/quick-step-livyn-single-plank-dark-brown-oak-luxury-vinyl-flooring-2105m-pack-sdh3684 for more contrast. The shelves are fine in whitewash, painting them may make the room feel smaller. Its better to let your items on display be the focus, than the shelves themselves. The darker bifold look more modern, and add extra dimension to the space. Depending on where the other window is, and how out of place it may look from the outside, you could replace it to go with the doors, or have the internal frame painted to match.

I'd take the salt and tablets out of the cupboard, put some kitchen roll on the shelf where the puddle was and see if it still happens. Not something i've heard of before.