I realized after I had posted my bit that this is the horse that was given to you. I finally put 2 and 2 together. I think he is just new to you and hubby, so a lot has to be worked out in the next few weeks.
In the very brief photos, the saddle does not look bad, but no one can tell from such casual photos. I only mentioned it as it is always the first thing one checks if the hrose is going hollow.
I like this horse a lot and I am certain he will come around in a short time. I agree that you need not trot or canter him under saddle for a bit, though you could certainly do that in a round pen or lungline. IF he hasnt' been ridden for a while, you will want to strengthen his back. I think that if you know he won't buck, then trotting some is cool. Save the canter for a bit, yet.
Anyway, you got more advice than you can chew on for now, so I'll just wish you well and look forward to more shots of you and Charlie. He has a ton of potential!