That is correct.
Also, if there was no stealth, then the jink save would be 5+
The order is you figure out your cover save due to intervening models/objects.
You have the option to jink, which gives you a cover save if you do.
You then apply modifiers to the cover save (from stealth, or auspex - as examples)
Also, per the wording on auspex, it specifically has nothing to do with the unit's cover save at that moment, take the following example;
A, B, and C are units.
x is terrain providing cover.
If B is targeted with an auspex by C (a situation wherein B has no cover) and is then fired upon by A (a situation where B now has cover) the auspex effect would still be applied, reducing the cover save from x.
A could also target B with an auspex, and fire on B, reducing B's cover. C could then fire on B, who would have no cover but a -1 effect to a cover save they couldn't take since they have no cover, but even if B then went to ground (getting +1) they would still have the -1 and still be denied the ability to get a cover save.