I have just gone thru all the ways to join these two and release them.
My idea was how to go thru other quest before going to Spellhold with them.
But here is the option I wanted to know if there is a bug in it. Because it gave me the option to have Kachiko in my party and not Yoshimo.

If you have Yoshimo in the party before you meet Kachiko but then kick him out before you meet her he goes to the CC or that is where you find him this time. So when you meet Kachiko she will offer to help you, if in turn you help her find Yoshimo. But then when you find him at the CC he has nothing to say to you so he will not join the group nor does Kachiko say any thing to him.

So is it broken or that is just the way it is?

If it's TS v6.05 then I suppose it's broken. It's another story with this WeiDU version. I have installed v5.5, and I do not touch v6.05 meanwhile.

If Angelo's Legacy will be in the next version, you won't have vacancies for them as other NeJ2 NPCs leave no place for a pair of Yoshimo-Kachiko. You'll send them to SBT, and then pick them only before sailing to Brynnlaw. They'll be obviously low in their levels if you do not bring them to Halruaa and to other quests in chapters 2-3. So I agree with you - "choices, choices...".

In my opinion, it's an advantage that now you can build a pure evil-neutral party from worthy NPCs.

Ok, yes it is v6.05 so it then must be broken. I had never tried that option before because it was always take them or don't.
Back to starting me evil party again.