Embedded questions without particle か

Question

（医師が患者に）薬を飲むか飲まないかを決めるのは、あなた自身ですよ。(pattern one)

お酒を飲む飲まないに関わりなく参加者には一人3000円払っていただきます。(pattern two)

I'd like to ask three questions.

The first one is: is "verb+か+verb+ないか" (pattern one) totally interchangeable with "verb+verb+ない" (pattern two)? If not, what is the difference between them (register, formality, frequency, etc.)?

The second one is: can all verbs be grammatically constructed into pattern one and pattern two?

The third one is: can 形容詞 and 形容動詞 be constructed into pattern two? e.g., 安い安くないを気にしている.

ご教授の程お願い致します。

Answer 1

1. I do think they are interchangeable. You should mentally picture 「・」 in the middle in the pattern two. Having か in-between does make it sound a little more polite.

2. Yes, and to understand that better, you should think of this more like 「AかBか」, such as 今日か明日か明後日か, 高いか安いか, 上か下か真ん中か

3. Yes, again because it's a simple enumeration.