@maria the initiative button follows this filter: Monster.IsNotBlank() AND Initiative.IsBlank(). Since we’re in a combined table, we only want to roll for monsters, and we only want to roll for monsters which are new to the fight. Then we calculate =floor(Random()*100 % 20 + 1), which approximates a D20 from the first two digits of a random number. Random() returns 0 < n < 1, so we have to multiply by 100 in order to use mod math. We add one post-mod because a d20 is 1 ≤ n ≤ 20, and mod20 returns 0 ≤ n ≤ 19. Then we round down because you always round down in 5e. 
Thinking more about the flip, I suppose I can use the fruit salad strategy (How to get all the unique values from a select list of select from table) to assign each instances of monsters to encounters, which has the benefit of keeping a record of NPCs that fight with players. Each view would filter is_player OR is_in_encounter, you know?
Why is it easier to design the template than it is to write my campaign?!