Named NPC stat blocks

[camdian]

I was wondering where we can find stat blocks for names NPC's if there are any. If not, should a DM just make them up?
For example, in Blakros matrimony, where would we find a stat block for Michelle, and Damian. I know for Eleanor it says to use the Noble Scion, which I guess could also be used for Michelle. Should a DM do the same for Damian (use a hell knight NPC)?

[The Great Rinaldo!]

Generally if there are no stats provided, it is because they aren't needed. In your example,

Spoiler:

None of those people should ever be involved in a combat. The final encounter even specifies that the hellknights are fighting other demons that are not included in the encounter, so as not to bog down the actual combat. And if someone were to challenge Damien or any of the other guests, I wouldn't bother with a combat, they would either laugh the player off or defeat them handily without need for dice.