In my personal experiance...

Nope.

When you put spirits into a body...

The body behaves erratically and with obnoxious intent.

whups...

Wrong spirits.

If they exist it must be possible to 'cohabitate'...

I have never noticed one. (they must be quieter than mice).

I have had experiences with both good and bad "things" and frankly it all freaks me out. It is hard enough to deal with the material world-going beyond is too much for me to handle.

My old house gave off the vibe of something having happened in it the first day we walked into it. Happenings were sporadic over the years, kitchen cabinets opening/closing, light going on, sounds of distinct doorbells ringing that were not the normal house doorbell, shadow figures, female voices, then before we moved out, a few hard kicks at my king bed. Thankfully, nothing too bizarre while the kids were home alone. For the most part, my family had a good experience in the rental home. We loved watching Ghost Hunters together. Our neighbors shared their odd experiences, so we knew there was nothing specific to our home.

I'd be kewl with it. When I first bought my house I found kids tinker toys in the basement and a lego man. I left them in the house. They are still downstairs. I didn't want any spirits here to get mad at me . And I've thoroughly Saged the house; so if they are here, they can be happy spirits

If you think one is there...

Focus your faith and prayers on seeing them 'float' to God.

Perhaps they have just lost the way.

Why not? Yeah as long as it wasn't trying to harm me in any way. I didn't know some could hold grudges :O. ??? They could come in handy. I could get him/her to clean the pots, or maybe vacuum. xD

Dusting would probably be easiest. Probably easier for them to blow the dust particles off of furniture than push a vacuum!

Spirits are everywhere. I am cool with them unless they are trying to give me a message and won't leave me alone. You know you can order them out of your home home right? They can't stay without your permission.

Lmao! Idk, i've seen ghosts do stranger things, when i was a child.

What kind of experiences? I recently saw one climb into a girl's locker at school, and when I told the girl to open the door and let her friend out - I got some weird looks. She opened the door, and all that was in there was her coat. I had to tell her the fur on her coat hood looked like hair. It sounded lame, even to me.

Did you have someone else witness what was happening?
It seems to me, it would be much easier to accept the idea if everyone saw the same things, no? Cohabitation is possible, the more understanding you have of the situation. Very difficult if there is malicious intent, though.