How is a "team set" defined?

I think for veterans on a team, its obvious -- the problem comes with
draft picks and free agents acquired before the season begins.

I'll give you an example: many checklists and website include DT
Kelvin Pritchett in their listing for '91 Dallas Cowboy teamsets. One
might argue that since the Cowboys drafted Pritchett in the first
round of the '91 draft, including him in the checklists of '91 Cowboy
teamsets makes sense.

But the fact is, Pritchett never played a down for Dallas -- he was a
draft-day trade to Detroit (some have said Dallas drafted Pritchett in
a pre-arranged deal with Detroit, in exchange for 2nd & 3rd round
picks).

So, some '91 RCs show Pritchett in his college jersey (Classic, Star
Pics); but other RCs show him in his Detroit uniform (Action Packed
Rookie Update, Wild Card).

Here's the flipside, from the same draft: some '91 teamset checklists
omit QB Bill Musgrave (Oregon); in fact, Musgrave went to the Cowboys'
training camp and was one of the final cuts that year, before signing
with the 49ers. Other CLs include Musgrave -- so which is correct?

I think a better case can be made for including Musgrave in Cowboy
teamsets for '91 than you can for Pritchett, although I think both
should probably be excluded since both actually played for other teams
in '91.

So, is there a generally recognized definition within the hobby of who
gets included in a teamset and who is excluded? Or is it up to the
individual collector?