Wow I am sorry this has happened to you. Unfortunately you have let this go on for quite long into their stay, so it is harder to tackle.
Just have a friendly chat and remind them that you work from home. Say you are finding it difficult to do so because they are also working in your space and having normal work conversations and telephone calls, which means you can't get your work done.
Indicate which times of the day you would be happy for them to use the living room for social activities ie after 6 p.m. and at whatever hours you choose at weekends.
Say if they want to have a space to work from you can recommend some work friendly cafe's or spaces they can rent by the day.
You shouldn't have to point out to them that they need to ensure their dog goes to the toilet outside and that they clear up any mess and dispose of it.
If they continue to break your rules, you can contact BNB and ask them to cancel the guests reservation.
I would follow this up by reiterating your conversation via bnb messaging.