Do I need a comma in this sentence?

I'm not entirely sure I understand the exact question, but:

1. "are these alcohol shakes or something else?"

If you capitalize the first letter of the sentence, it's perfectly fine. It does not need a comma.

"Are these alcohol shakes or something else?"

2. "are these alcohol shakes, or is it something else?"

You can write it with or without a comma. Personally, I wouldn't use a comma. However, if this were dialogue in a play, for example, the comma might indicate that the speaker should pause briefly.

You must make the subject of the second thought agree with the first thought, however.

Are these (plural) ==> are they (plural)

You should also capitalize the first letter of the sentence.

"Are these alcohol shakes, or are they something else?"