In order then

partially blow up the tubes, then blow up the floor, then finish the tubes.

If it planes, you can take the rubber bung out whilst going along to drain the water. If it doesn't, just take it out when you've lifted the dinghy (its a good idea to have a small hand pump to empty water out to make it lighter to lift)

Yes don't add oil to the fuel, but do check the oil level occasionally and store it the right way up

Steer by turning it side to side

With the dinghy fully inflated run a straight edge along the base/keel, and then set the tilt of the engine so the cavitation plate is parallel to the straight edge, and an inch or so lower

If you can clean it after each use, great, if you can't, don't worry they're pretty resilient

Yes, its a cracking combination and a perfect ship to shore tender