Recreating Final Fantasy Tactics: Dynamic Enemy Stats Help

Quite simply, as vanilla as possible without a Pro subscription to access modding API, I want to do a character sheet system for a campaign where the mechanics work Final Fantasy Tactics-style, one being where i have template NPCs for enemy classes, for example I want to have a Level 24 Thief with three Level 15 Thief mooks, or a Level 90 dragon and its level 6 hatchlings. They have appropriate stats for their levels or challenge rating, but they share a character sheet as a baseline. How are some ways I can give the enemies different dynamic stats and different attack strengths, defence values, equipment, etc, without having to make separate character sheets for each variant? Otherwise, I'm going to literally drown over time in having to make every variant from level 1 to 99 for each class and monster over time. I'm using the default 2014 Roll20 sheet as a baseline and trying to work with its code from there.

First off, to use custom character sheets, you need a pro subscription to start with. Moreover, all the character sheets by Roll20 are proprietary, so you can't use it as a base for a custom character sheet. But, if you were to have a custom character sheet, it should be possible to have all those values scale based on the level. EDIT: Though if the only input variables are the level and the class, then you could do something sheetless, depending on how complex stuff you need, using tokens and macros.