How does the power drop for multi target moves work in these situations?

Question

I case you were unaware (Like Dondozo is) in a double battle, moves that hit multiple targets get their power decreased by 75% (50% in gen III I think.) I have a few questions about how this works in the following scenarios:

1. If there is only one opposing Pokemon left, but the move hits your partner as well, does it still get the power decrease?
2. If one of the opposing Pokemon uses Protect, so the move only hits one of the opposing Pokemon, does it still get the power decrease?
3. If one of the opposing Pokemon is immune to the move typewise, does it still get the power decrease?
4. If one of the opposing Pokemon is immune to the move by an ability like Water Absorb/Flash Fire, does it still get the power decrease?
5. If the move misses one of the opposing Pokemon and hits the other, does it still get the power decrease?

I'm sorry if this is too complicated to answer easily, but I didn't want to ask each question individually, because they are very similar and many of them probably have similar answers.

This could probably be solved by a few quick tests on Showdown!

Comments

I think the power decrease depends on the number of targets, not the number of hits. So the answer to most of these questions is probably yes.

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I am aware of that, and I also have a guess as to what the answers for these are. I would like someone to either test these scenarios out to give a definite answer or have a reliable source for each situation. The reason why I asked this question is because I want an answer with proof, not an "I think" or a "They Probably".