Match the wood floor in the largest room (or the one that the client likes the best) and then replace the wood in the other room. You want the wood to match in all the rooms, or it will always look like an ooops.

I totally agree with Sammie. This is such a basic question for someone who has clients. Are you a designer?

I'm all for breaking rules but in this case.... 3 different wood floors and 2 different tile floors? And yet the homeowner can afford someone to help advise them on decisions? Hmm. Best advice is to unify the flooring throughout, or as close to that goal as possible.

For myself, we have tile in our kitchen, and thank goodness we chose that. Most people recommend wood flooring in the kitchen, but with many dogs, kids and kids' friends, we have a bustling traffic and I appreciate not having to worry about spills, etc. However most people will be fine with wood throughout.

I'd use the same wood as in the room adjacent with the fireplace. It doesn't matter if the planks run the other way if that's the best. You probably will need a transition strip anyway.

Wood in the kitchen is not a problem as long as it is a hard wood, like oak, and it's finished correctly. I've had mine in a kitchen for over 8 years, and have a dog and grandchildren running around, and it still looks great. It's the easiest to care for kitchen floor I've ever had. Better than sheet vinyl, tile or laminate (which is the worst).

get the same oak plank size and same species size, and stain it as close as you can to the other (unless they want to completely re-stain the other part)

it's fine if it runs another way

https://www.sopocottage.com/2013/04/mixing-old-and-new-hardwood-floors.html

get a matching transition piece for the one going the other way

I would not use wood floor in a kitchen where it's exposed to water.

I'd select a larger scale tile for the kitchen floor to update the appearance.

Wood floors in kitchens have been around for a long time and IMO still the best choice if there is wood in the other spaces . I do wonder why you are asking us if this is your client. get unfinished floor in the spaces you are changing and have them finishedd to match You do need to match wood species for sure.

We have different wood floors in different rooms, which we did on purpose. It doesn't look like an "oops", as the rooms serve different purposes and there's no reason for them not to be distinct. (we also don't paint all of our walls in the house the same colors, horrors!) The current mania for making everything match will pass in time.

Hardwood is, IMO, the best flooring for kitchens I've ever had. Easy on the feet, looks nice, and you usually get at least one bounce to catch dropped objects. Have done vinyl, ceramic tile, and even, heaven forbid, carpet (it was a rental). In an old house I'd certainly consider real linoleum, but have been perfectly happy with maple for the last several decades. Ceramic tile would be my last choice (well, not counting carpet).

Whether or not you have the same exact flooring in all the rooms in a house depends on the layout. In an open layout, where all the rooms are open to each other, having different flooring just looks chopped up. However, in a traditional home where there are rooms, floors and wings separated by walls, doors, etc., it's not a problem. Clearly bathrooms and kitchens can have different flooring than living areas. Bedrooms can be carpeted while hallways are not. Making blanket statements using "always" and "never" is rarely helpful when trying to design a home or a room. Nothing is ever perfect or the same, and each project requires a fresh eye, while keeping basic design principles in mind.

We have an open concept great room/kitchen/diining room and everything is the same wood flooring. I inherited tile in the kitchen but matched the floor to the great room when we refaced. The wood planks in the kitchen run perpendicular to the great room. You can't tell unless you really "look" at the transition.

The only change in flooring is when you get to the laundry room/mud room area. Those are tile.

I also prefer wood in a kitchen because it's easiest on your back. And I have never had a problem with "water". Small spills wipe up if your floor is properly sealed.

I agree @RedRyder, water is only a problem if you haven't sealed the wood properly. Mine is 8 years old and has no water damage. And I don't baby anything in my kitchen, including the marble countertops.

Water finds its own way. Sealing wood floors makes no difference. If there is a leak from an ice maker or dishwasher and the water finds a way under the wood at the edge the floor will buckle.

I had a leak in my AC unit and the water leaked from the furnace room, UNDER THE CERAMIC TILE FOYER, and found its way to my den and ruined my laminate floor.

One more comment--if you are a designer, especially one just starting out, you don't learn everything in design school. But if you have a Houzz "Pro" account, you can go to the "Pro-to-Pro" section and get advice there.

I've had real site finished wood floors over basements and crawls spaces. In the house we built in FL I have engineered wood floors on a cement slab.

A bad enough leak will ruin any floor. I have had wood floor throughout the 4 houses I have owned and never had a problem. I'm not going to decorate based on an event that has a very small chance of happening while I own the house! Life is too short to live with flooring you don't love and I have insurance if something unexpected does happen.

Thanks all! We decided to go with a slate / stone looking flooring option since it will also go in the mud room and bathroom. Really appreciate all the input! Thank you!