For the bullet point #7 you quoted Lal (and I have not checked the post):
7. Thus to attain Nibbāna is to attain the perfectly purified mind, which refuses to be burden with a physical body that leads to decay and rebirth repeatedly (and thus to dukkha).
… we can also read it as:
7. Thus to attain Nibbāna is to attain the perfectly purified mind, which refuses to be burden with a FUTURE physical body that leads to decay and rebirth repeatedly (and thus to dukkha).
A common theme of this site is ending FUTURE suffering in the rebirth process.
You can also look at this from the standpoint of abhidhamma to explore the various stages of purity. The Abhidhamma section of the site goes into details of what I list in brief here.
There are 4 ultimate entities: cittā, cetasikā, rūpā, Nibbāna
cittā and cetasikā are mind
rūpā are matter: hadaya vatthu, pasada rūpā, etc.
cittā, cetasikā, rūpā are in this world of 31 realms. Nibbāna is not.
For a mundane person, cittā are contaminated in 9 stages. For an arahant, in his day to day life (saupadisesa nibbana), cittā are “pure” in this sense: they go through just 3 stages of the 9 stages.
Also, there are pure cittā, i.e. cittā with just the 7 universal cetasikā. They are called Pabhassara cittā. An arahant experiences Pabhassara cittā in Arahant phala samapatti.
Up to now there is still hadaya vatthu.
Then there is Nirodha samapatti, where there are no cittā, thus no hadaya vatthu. But the physical body is still alive.
Finally, there is parinibbana, at the death of the physical body of an arahant or buddha. cittā, cetasikā, rūpā are gone. Just Nibbāna.
Again, the whole abhidhamma section (a treasure trove actually) explains these in details, but a couple of links may be of interest to start with: