Welcome to the forum. Looking forward to your post. There is a lot of great fishing in your area.
I have posted a picture of the pontoon boat you are asking about.
You are asking a lot from one boat. I am not sure if this is what you want. Here is what I think. You should figure out your primary use and chose a boat that best meets that requirement. In the part of the Snake you fish do they use jet boats or drift boats? You may be better off with a drift boat. Some drift boats are equipped with a motor. It is not a great boat with a motor due to the extreme rocker used in a drift boat. It will get you back up the river to re-float a section of river. It would also work in a lake.
As to the McKenzie Drifter. It will be well built and should work with a 5hp motor. I would check to make sure it is rated for a motor and what size. The oars sold with the boat are too short and you should up grade to 9' oars. The rowing position is too far back and it will be hard to spin the boat from that position. It does look like you have some adjustment and could move the rear position forward. The problem is you will put the weight bias toward the front and this would affect the rowing performance. The oars should be as close to the center of the boat as you can get.