MLC, you can't have less than 12 frames for NPC movement.
Two frame animations are ♥♥♥♥ and unless you only want the NPCs to walk in three directions you'll need them to have facings for all of them.
Plus you really should have more than 3 frames in any case.
So that is still 120 (and wtf, 20 NPCs that's only enough for three towns)
And we haven't even started talking about tilesets, there would be over 1000 tiles on their own.

And even after making your own imaginary figures you still weren't able to get under 1000 and prove me wrong

Maybe I estimated low on the character sprites, but lets see. 4 x 4... 16. So, 16 per. Multiply by 20... 320. Ok, you got me there.
As for how many NPCs, you never see generic characters called "Villager"? You never see games that have 4 male characters and use them in every town in that region? Wow!

Who said 3 towns? or 20 hours?
I know it wasn't the OP.

Holy ♥♥♥♥ shut up you guys.

"He started it!"

Well, I proved my point, and I guess this is a bit childish.