I don't care for using two wood floors that don't match in spaces that are open to each other - unless you can blend the colors and use some type of pattern that is totally different between the two. What are the reasons that the person who is recommending hardwoods is giving to back up their recommendation? Why can't you use a site finished hardwood and have it stained to match the existing? It takes some time to get the stain right and it takes a more experienced flooring person, but it can be done. If you want tile, I don't see why that wouldn't work - but we haven't seen your space and don't know the specifics about the construction of your home.

Thanks for the feedback, I've attached a photo that shows what the transition would be.

I see no reason tile could not be used, you just need to coordinate with your fireplace stone and not clash with it. I also see nothing in your wood flooring that could not be duplicated with a good flooring company using site finished material.