Lisa does not have unlimited access to Dragon and so knows far less about us and our plans, strengths and weaknesses.
Lisa is a verdammt Thinker 7.
The S-class parahuman she has unlimited access to in this case is Wyld, even though she does have Dragon and Narwhal's ears.
She has actively attempted to disrupt Alchemical recruitment by messing with Aisha.
She helped set up our father to attempt to kill us, and her intelligence was instrumental in helping Coil put a bullet in our mouth.
Materially, she has interfered more with our cause than Saint has.
We aren't out to gank her, or name her a pressing threat.
You are basically repeating the argument you did earlier with Cauldron, just swapping Lisa this time. Just because Cauldron and Lisa are potentially risky to us, does not somehow make Saint a non-issue.
Saint is not a non-issue.
Saint is a pawn.
As he is, no one else can wield him.
Every other action you have proposed taking puts him into play for actual players to use.
To turn him from an occasional irritant to an actual problem.
Saint however is unstable and could do anything at any moment.
Mentally unstable?
Citation please.
Given the perception abilities Taylor has (including optical charms), the lack of dna evidence alchemicals leave, the ability to shroud and hide even from shards (and hide others), Sakis ability to shapeshift and so on, the probability that Ziz could somehow get us via Saint is absurdly small. Besides, if she can, then we are fucked already. (see next point).
You do realize that we are pretty high visibility, right?
And that a period when we vanish, followed by the abduction/death of a sometime adversary will draw attention, right?
Or that Saint's lair has cameras, and possibly off-site backups?
Our opposition isn't stupid.
Which is ofcourse why we obeyed the law and the legal kill-orders made by the courts on extremely dangerous terrorists parahumans of great power that have murdered thousands upon thousands, instead of illegally faking their deaths in order to hand them over to a vast conspiracy that is manipulating everyone, performing highly illegal human experiments and doing all other sort of fun stuff and will likely do who knows what with the parahumans we gave them. Oh right, we did what was beneficial to us personally, regardless of laws or goverment.

We exchanged 3 people for information leading to saving the city of Philadelphia, and the worlds.
That was our
job.
The disposition of the Niners in particular is arguably covered by the note that gave us tactical command during the crisis, which went "Granted unusual breadth of discretion."
We would have reported it in by now if not for the risk of, y'know, setting off the verdammt apocalypse.
We do not rule.
We are not in this shit for personal gain, else we'd sit in a lab and crank out spidersilk and tinkertech for money like the Youth Guard would like us to do.
We are not even in it for revenge, or we wouldn't have put our body between Siberian and Lisa, or traded Manton to Cauldron instead of putting a bullet in his head.
So please do not equate trading Manton, Mannequin and Shatterbird in return for favors with doing our job for fucking
corruption.
Oh, and if Ziz could somehow magically get us with Saint, she sure as hell could with Cauldron (and cause us far more damage).
Cauldron are based in a different dimension.
Ziz has interfered extradimensionally once that we know of, and that was to bring over the Travellers.
She does not operate on Earth Aleph, or Earth S, or Earth Tsav.
Her base of operations is here.
If any fuckery is going down, the main focus will be here.
And Saint is based here.
Do the math.