Yes, you can switch brands with no problems at all. Just make sure you use the exact weight that the manufacture of your vehicle recommends.
Yes, and you can even mix them together.
YES. The only hazard in changing brands is interactions between the add on packages (detergents and chemicals), they are not serious, but they can make a car smoke a little after the first change with a new brand.
That's okay.
It is a gas/oil mix motor, you don't change the oil.
Yes, as long as you use the correct weight.
No harm will come from topping off the oil level with a different brand. All oil manufacturers use a similar oil additive package. I would stick to one quality brand of oil. More important is using the designate API grade and viscosity.
All major brands of motor oil are manufactured to the same standards. To pick a best if impossible. But saying that Synthetic is superior to conventional oil.
Cambie aceite motor= change the motor oil
yes it is fine but of course synthetic is the best to use if you can. Double check your oil requirements with your owner's manual. If it states that normal oil is okay, then go ahead. If your owner's manual dictates Synthetics, then DO NOT switch.
no
Yes, as long as they both meet manufacturer specs, no issues.
How do you change the oil in a 1967 3Hp Evin-rude outboard motor?