There are three important factors to consider when you’re choosing a recommender-

How long you have known them What they have worked on with you, and Their qualifications
Read more about each of these factors here

First of all, calm down

If your recommender is your Manager, ask your Team Leader to recommend you
You can use the same content

If it's a teacher, ask another professor to do the same
If they have already seen you do what's mentioned in the letter, reuse it
Otherwise, tweak your content a bit and then ask them to sign it

Check your application status
If it says "Under review" there's nothing to worry about
Otherwise, email the admissions department and make sure they got the LOR

Use a standard font like Times new roman and size 12

No, it will not.
But make sure you use the college/company letterhead to signify your recommender's authority.

You could also ask people you have worked with, outside of your restaurant
But make sure they are at a level better than yours

Make one and use it for all
Just make sure you delete the author details from properties, though

You should have both
Which is easier if you're working
If you're a student, get an internship or volunteer and get a non-academic LOR

Pen down your LOR in the standard format, covering all the aspects of a regular LOR
Once this is done, it should be easy for you to divide and edit your content accordingly
Reach out to me in case you need any help

Depends
If you're only applying to 2 or 3...
And if your recommenders are okay with it...
You can
Still, I advise against it

You can refer this blog to see how to write it

One from the high school teacher
Two from diploma teachers

Hi Sid,
Yes, it will.
If you're worried about submitting them late, you can email the university and ask for an extension.
But make sure to submit it.
Otherwise, your application will be considered incomplete.