An alternative to persistent level templates, is to make the items/triggers/characters that you want to have the same UUID everywhere as global.
A major purpose of non-persistent regular level templates is to be able to insert the same level multiple times in different places, with every instance being completely independent of every other instance. Hence, the fact that UUIDs for items inside the level templates are regenerated in indeed inherent to that. There's no easy way to get those UUIDs, unfortunately (the "easiest" way I know of is interacting with the items and then checking osirislog.log).
