Handgun permit class & application signatures

I just recently found out that the application calls for a few other people sign off on your "moral character". Are there any restrictions on who can & can't do that (and have their signature treated as valid by the government)?

The first thing it made me think of this was the fact that the permit requires taking a class anyway and the local place offering the classes also says they'll help you make sure the form is filled in right, so it seems like the automatic thing for the members of every class to do is just have the class's other members sign each other's forms. Then I thought that's so easy there must be a restriction against it.

Then the idea of restrictions on who can sign off for you got me thinking about other things people might do instead... like what would stop somebody from using a random stranger, whether by paying them or by meeting a "screw the government & their forms" type in a gun store. Is there a requirement that it be somebody who actually knows you? If so, how would they know?

Do they require not only a name but also an ID number, phone number, address, or "how I know this person"? Do they check the names & backgrounds and disqualify people & tell you to try again, for example if they find out that one of your people is a felon or on the sex criminal list or such?