(If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.) If Maester Seymour is no longer on the battlefield when its first ability resolves, use its power as it last existed on the battlefield to determine how many +1/+1 counters to put on the target creature
as you can see in the base sets gallery, these are numbered between 1 and 204, which is the number of cards in the Azurite Sea set
If you gain an amount of life "for each" of something or "equal to the number" of something, that life is gained as one event and Minwu's last ability triggers only once
Farideh, Devil's Chosen is also an interesting payoff, allowing you to draw a card whenever you roll a 10 or greater (the base die is usually a d20, mind you)
Lastly, if your deck is already doing shenanigans with extra attack steps, then you get bonus benefits from Eriniscards like Aggravated Assault and Moraug, Fury of Akoum