Celebrim
Legend
That's my problem.
I'm not sure that I missed that. It's very much a "I learned to play as a player" sort of problem, and very much you treating the NPCs as PCs.
It's very common for players to go from stats to personality in the process of figuring out what their character is. Relatively few players start with a non-mechanical background and move from that to mechanics. As a GM though, you have to reverse that and learn to figure out who you want the NPC to be, and then fill in the stats later to make that happen as needed. It's ok to be inspired by mechanics, but you shouldn't be as dependent on them as you are claiming to be.
Fortunately, knowing you have a problem is half the battle. By all means create those complete NPCs. But understand the seven sentences that make the NPC memorable are vastly more important than the stat blocks. For everything but an NPC meant to be a combat challenge, if you must do without one or the other, do without the stat blocks.
Being very confident about your demographics is helpful here as well. For example, Tella in my game is almost certainly a 1st level commoner, with no stat above 12 and a total point buy of no more than 15 points. If Tella is unusual - her background has given her the survival skills of a 1st level rogue - that aspect of her background will be more prominent in my mind than even her class is. If Tella is exceptionally nimble I'll note that before I note in parenthesis her heroic level dexterity "(DEX 16)".
One thing you I think really need to get your head around is that for all you claim to be inspired by mechanics, nothing in Tella's mechanics implements who you've made Tella in your description of her. She's not nearly the port from the mechanics you think that she is, and in my game to annotate what you've claimed about Tella's personality as mechanics would require much more precision like Insanity (Hebophrenia) and Misanthrope (Animals). Starting where you ended up with her flavor would have led me to very different places mechanically because unlike typical D&D, my homebrew very much implements flavor as mechanics. You may be far less hidebound to mechanics than you think you are.