1. I don't think there's a chance. Calment's age is such an outlier that even that has gone under dispute recently. The only reason she was verified is because there was such an extensive background of records to back up her claimed age, which all of these claimants don't have.
2. See above.
3. It's very unpredictable to say at such an old age, but having a healthy lifestyle definitely makes the odds more likely.
4. Some scientists have actually placed an upper limit on human lifespan at around 125 or 130, though this is also a point of dispute, and we won't be able to truly tell until an apt amount of medical advances are made.
5. The Gerontology Research Group at https://grg.org/ should host or at least link to a few articles or publications relating to Gerontology.
6. Again, unpredictable, but if any of the currently living supercenteneranians are to pull it off, Tanaka has the best chance. When she took the spot of oldest living person, people noted how healthy she seemed for her age.