If it were for my place, I will continue mudroom tiles into pantry. Bring the kitchen hardwood till the opening and have clean transition to tiles there.

Thats what the builder did, but we were unsure if correct since we saw hardwood in a different house.

If you want hardwood you can certainly do that, I personally like fewer transitions and more consistency. Would you have hardwood in Guest Room or carpet? If you are going with hardwood in guest room, it might be more consistent to have hardwood in pantry.

What's the flooring plan for the guest room? If wood, I'd consider doing the wood in the pantry too. If it'll be carpet, that I'd stick with tile in the mudroom.

Hardwood in guest room. Since pantry was already tiled and matches mudroom, my only options is to rip it out if we feel that strong against it.

Don't rip it out. Tile in the pantry is perfectly fine!

I personally prefer fewer transitions, so I would keep the tile. We have a closet and powder room connected to our mudroom and I plan on the flooring for each to be the same.

Tile of course. That room only touches the mudroom, which is tile.

I would have said tile right from the beginning. The mudroom and the pantry are "working" areas where you're coming in from the outside. The guest bedroom isn't. The builder got it right.

Another vote for tile. Less flooring transitions and if something liquid spills, it won't damage any hardwoods. We were cleaning out our pantry recently and discovered vegetable oil that had spilled on the floor of our hardwood pantry (ours is a reach-in in the kitchen). It did enough damage that we had to rip it out and replace the boards.

Same as mudroom - tile. If you look at the plan, it is a cohesive logical whole.