Minimum amount of personel needed to sign up at Horntail?

So is it like Zakum with 5 people needed in the squad, no need for them to even be online? I think it is only 4 guys needed at PB.
I heard somewhere that soloers can enter HT even though the HT glitch is still there. Is this the case?

Thx for your time. xP

6 for HT, and it works the same as PB/Zak.

Anyone can HT until 30 people enter the cave. After this 30, only people on that list can enter, and they can only enter solo.

And obviously this resets after each SC.

Thank you very much.