Lovetoplant, the Florida murcott fruit is also grafted on the same tree as my Honey murcott and the third murcott variety so it's easy for me to compare the ripening of these fruits on my tree. The Florida murcott ripens last for me, it just started to become fully ripe now on half the tree so it should be good to eat in Feb-Mar. I noticed that there are two different varieties of mandarin which is called Florida murcott, I have both types. Type 1 has the thin skin, bright orange color, sticks to flesh, many seeds, average sweet unless you pick it at the perfect time. Type 2 has the thinner skin, not as bright orange, more like the color of Honey mandarin yellow, skin sticks to flesh, many seeds, but very sweet. I would say this type 2 murcott I have is as sweet as the CA Honey but both has some acidic taste which I like.
I couldn't tell you which citrus variety seeds grow true to parent fruit. I think it was mentioned Sumo seeds will give true Sumo fruits, I will find out when my seedling tree fruits in a few years.