confusing conditional sentences

Hello dear teachers,
Could you please tell me how the following sentences differ form one another in meaning(s)?
Here are the sentences;
1). If I give you $5, will you wash my car?
If I gave you $5, would you wash my car?
If I were to give you $5, would you wash my car?

2).If he is found guilty, he would be given death penalty.
If found guilty, he would be given death penalty.
If he were found guilty, he would be given....
If he were to be found guilty, he would be given....

One of my friends says that case 2, 'if he were found guilty, he would
be given...' is incorrect. He says, "I will use this structure only if something is impossible." He also gives an example 'If I were a bird, I would fly to Africa.'
He(my friend) further says that I will not use sentence 3 (in case 2) unless the possibility of him found guilty and given the death penalty is Zero/ almost zero.

Does the structure/ pattern "if + past, would..." always talk about the future?
Could you please clear it up?

Thanks
LB