Is such a battery of arguments permissible in legal contexts, e.g. in a criminal defense?
Using multiple logically inconsistent defenses is generally allowed in the US.
On the other hand, I've seen a ton of "I didn't do x, and even if I did do X it was acceptable because Y" where Y was the worse crime... that somehow still succeeded as a defense. Thankfully not in a court of law, but public opinion is weird.
2. The defence is expected to lie, and if the prosecution cannot prove that every single one of the defence's arguments are lies, then the jury cannot convict beyond reasonable doubt.
3. The jury should assume that the prosecution is lying by default, and acquit if the prosecution does not convince them otherwise.
The defence is expressly prohibited from lying. Lawyers have a so called duty of candor [1] outlining this. Defendants testify under oath to make this clear to them. Defence attorneys must disclose to the court if their client lies to the court (and they can't convince their client to voluntarily disclose it instead) [2].
That doesn't mean people are expected to take defendants at their word during trial, juries are allowed to decide they think that someone was lying, but they aren't expected to lie.
[1] https://definitions.uslegal.com/d/duty-of-candor/
[2] https://www.eiglarshlaw.com/when-clients-liewhat-must-you-do...
(In practice, humans don't consistently compartmentalize well enough to reliably avoid this, though.)
Both sides agreed that the man was in the car with his pants down (defense claimed defendant was looking for a tick on his leg). The defense argued that with the window tinting on the car window, it was not possible to see into the car.
My dad's takeaway from this was that one of these must be true:
1. Someone coincidentally accused someone of having their pants down without being able to see them, and happened to be right
2. The window was rolled down
3. The defense is presenting false evidence
If some charge requires both [A] and [B] for the accused to be guilty, then this argument is that it's neither [A] nor [B], but the defendant is innocent if they can prove either half of the argument, since the condition is "[A] and [B]", not "[A] or [B]".
No, you don't.
It's just if you are charged with an offense that requires intent, the question of self-defense (or any other excuse) is moot if the prosecutor can't prove intent beyond a reasonable doubt in the first place.
If you are charged with an offense that doesn't require intent, like involuntary manslaughter, you don't have to argue intent to kill to use self-defense as an excuse.
And even of you are charged with an intent crime, you don't need to grant intent to argue self-defense.