With the walking, I would build it a little at a time. You also don't know... maybe he he has history with a wooded area. If so, you'll have to replace his memories with pleasant ones, a little at a time. Taking cues from Romie and Meg will help as well.
As far as the chair, I would remove him from my lap and work on a "down" with a treat. If he's eager to please and food motivated, he'll catch on quickly. Then you can move straight to the "down" commad.
I've never used squirt bottles on any of the boys. They all liked treats so much, we just used that with commands.
I am thinking Milo is young, and my Jake came to me very young. The exuberance can be trying at times, but Jake is settled most of the time now that he is approaching the ripe old age of 5