For those considering bringing another adult dogs into your home. I do a few things that makes transition easier. All food, treats, and toys are given away from each other. No toys are left out, and couch, bed privileges are very limited. You do short, active play time, and then separate the dogs. You are learning about them, and they are learning about their new surroundings.
When we eat. Either no dog is out, or only one dog is out. As you learn the dog, and they become comfortable with your dog. You can start adding things back.
Even with good temperament dogs, you may have an occasional grumble. One may grumble to tell another stop messing with me. The other dog should stop, and go on their merry way. I don't interfere when both are speaking normal dog language, as there is no escalation.
I just keep a watchful eye, for any guarding issues.
And watch their body language, around things of higher-value. By doing this you can stop a problem from occurring, before it becomes a problem.
Jasper and Hunter have very good temperaments. Even with knowing that, I handled them the same way, as I would handle unknown dogs.
Not all those who wander are lost.
Life is just a leap of faith.
Spread your arms and hold your breath and always trust your cape.
Two things define you. Your patience when you have nothing, and your attitude when you have everything.