Beginner theme question - removed letters

[spski]

I'm working on a puzzle with a theme where the answer is missing some letters.

Is it legitimate to have the remaining part of the answer not be a valid word?  (e.g. imagine if all themed answers were missing TRY, and the clue was "geopolitical unit" yielding COUNTRY, which went into the grid as the 4 letter word COUN)

Do the missing letters have to be from the same part of all answers (e.g. all from the end of the answers: COUNTRY, PANTRY, SOPHISTRY), or can I vary it across beginning, ending and middle (COUNTRY, RETRYING, TRYPTOPHAN)?

I'm just making this for fun, but I'd like to do it in the style of the NYT or LAT. 

[mmcbs]

The accepted treatment of drop letter(s) themes is that the remaining letters form a real word. The letter(s) don't need to be removed from the same position, but it would not be elegant if all but one were from the same position and the other one was from another position.

[spski]

Thanks for the tips.