All good advice, but I’d recommend against removing chairs etc. I have family members with mobility issues and the biggest reason they’re upset and feel left out at parties is because everyone is standing and they don’t feel like they’re included because of it. Have seated areas, and have a couple of chairs in locations that let standing people chat with the people who need to sit too. Make it such that people who usually stand will naturally sit and hang out with the sitters as a part of the rotation.