I'm having a little trouble with the definition of "Eco-".
I think I am "Eco-" friendly as regards use of chemical sprays in the house and garden, and I try and buy products which are labelled as bio-degradable, and non-destructive to the environment.
However, that does not mean, necessarily, totally fragrance- or chemical-free, and it doesn't mean that every practice I use in the house, like recycling and waste-disposal, is 100% perfect. And it doesn't necessarily mean allergen-free. People can be allergic to almost anything, including house dust (more specifically, mites which occur in house dust). My sister was the most allergic person I ever knew, until she went for desensitization treatments. There wasn't any way to prevent triggering some of her allergies.
I have solar hot water, but I also use natural gas. I use glass and stainless steel, but I also use plastic bin liners. I prefer soap to antibacterial handwashes, but provide both for guest use.
I think "Eco-" is a continuum, and not a state, and even if one implements a search based on "Eco-", there should still be questions and answers back and forth between host and guest, to establish whether or not a listing is suitable for both parties, based on their specific needs.