Using all sorts of whimsical names really makes no sense; there is no consistencey for naming, and it will delay and impede the possibility of becoming recognised. There are too many ways that different judges judge based upon what is entered on coop tags versus what is in the cage. Some judge based upon the variety present in the cage, regardless of how it is entered, and if there are birds of the same variety, however they are entered, the judge will judge them together. Other judges will judge only as they are entered. So you might have three porcelains entered under different names and they will not be compared. I have seen good quality birds of recognised varieties disqualified becuase their coop card listed a different variety, to which they did not conform (for example a blue in a cage marked partridge).
Isabel is lavender diluted buff, it really should NOT show any lavender--same as a buff should not show any black. There is a standard for isabel, although it is not an American standard. If you have a bird who is almost completely isabel with very little lavender, by all means enter it as isabel, but if there is a fair amount of lavender, that is not a good plan.
Pastel is probably the only name that makes a lot of sense to me other than porcelain. I am pretty sure that George's long term goals for this variety that he created in silkies was to breed in the mottled gene. That is one of my plans, although at this point I am stabilizing mottled in my birds. This has been far more difficult than chocolate/khaki. I foresee that in 2 to 3 years I might have a true porcelain silkie.