How long have you got, and how many opinions do you want?
Your list looks good, but opinions will differ and there is no Linn police force - it’s only meant to be for playing music after all, so whatever works for you is right.
I also suspect upgrade priorities depend on what you have before you upgrade.
For example, most here (including me) would rate a Radikal well above a Lingo 4, but if you have an old Valhalla-era sub-chassis, then I would definitely do that first - unless that cartridge is an old K9 hanging off an old Basil arm, in which case (say) both a Lingo and a Kore can be put on the ‘plenty good enough for now’ list, and more basic options may also outlast arm and cartridge.
I also rate a Karousel, but if I still had a Cirkus with a Lingo 1 or Valhalla (or a really not great arm, cartridge, phono etc), then I would do any or all of those before the bearing.
I would also say that I have and like a Stiletto, so have gone even further on top plate, base and the plinth between. However, I would put Ekos (or Aro for the hardcore enthusiast?) much higher in importance than any of those.
I’d also put a good phono stage higher on the list, even if you don’t go quite as far as an Aura - DV P75 mk 4 is amazing SQ per £ and a Superline. is imho even better.
Some will say that a Stiletto is not made by Linn and this it is no longer an LP12 and/ or should not be considered/ discussed or included on the list at all, even if it does sound slightly better (which it does). That will probably be their stance on top plates too.
A smaller number will only discuss Linn phono stages and cartridges. That seems more consistent than allowing discussion of other choices here but not on top plate, but even harder to defend on SQ per £.
One other thing you could add to the list is T-cable versus old cable.
More important than that to many of us would probably be what is under your LP12 - there is not much point having a £5k cartridge if it is on a sideboard and not much point having one at all if the needle bounces every time you walk across the room.
It is also not great if the TT power supply box is really close (physically or electronically) to the power feeding amplification, or if any of the kit is on a shaky house ring supply - does it make a noise when the fridge is opened or sound worse if you plug in a kettle?
There have been threads on almost all these topics, and for good reason. That alone probably tells you that there will not be widely agreed rankings/ answers to almost any of this.
In any case, it seems that you have a high spec LP12 and like it. Job done, surely?