grammar - How to simplify "noun phrase" + "noun phrase" structure

Example 1: User 1 and user 2 have the same request.
In this example, I would like to remove the second "user" to shorten the sentence. I wonder if I need to change the first "User" to be "Users". If not, then I do not know how the following writing style is correct.

In our technical writing, we often use "Figs. 1, 2, and 3" to mean "Figures 1, 2, and 3". Since I cannot find a related grammar for such a usage, can anyone give me some hint or tell me which one is correct. (It will be better if there is an explanation)

Another example is to simplify "from user 1 to user 2." I do not know which one of the following two writing is correct: "from users 1 to 2" and "from user 1 to 2."

Thanks!