Tried to summon her besides Lobo after beating EB, just like she wished. Was kinda disappointed nothing happened...

There's no way I could have known about that arbitrary break point without reading a full game summary ahead of time. It's an OPEN WORLD game, and losing a major, hard limited upgrade item feels for missing/not going through one of DOZENS of caves feels really bad. Worse, this is only a two step quest - no interactions that would push you in the right direction. There's nothing that would clue you in to the urgency, nothing that really points you that direction, and no need for the item before you reach the break point because it's so short. Pretty much any other NPC quest in souls can be missed, but at least you knew you were on the quest so you could try not to fail it most of the time. I missed this because I played the game in a totally normal way, and I think I get to be a little salty about that.

FOUND THE ALBINAURIC WOMAN

In case someone else is as dumb as me: the prompt to summon her at the giant woman is a few feet beck from the woman, closer to the grace. If you're right in front of her you won't get the option.

But what about the giant lady? DLC or is Latenna's questline unfinished?

I wish completing her questline would allow us to turn Lobo into a spirit to upgrade her into Latenna & Lobo ashes, maybe use Seluvis's Amber draught & his potion combined.

She didn't talk to me when I approached Castle Sol even if she joined me as Spirit :(

So I missed the cave at the beginning of the game…now I can’t get a Somber stone because of it??

She calls Lobo her “better half”.
If I’m not mistaken, this term describes someone who is your romantic and/or sexual partner.
Am I getting this right?

I’d like to think that her being a cripple means that he’s quite literally her better half, from the bottom down.

Lobo means Wolf in portuguese as well...