The varieties I would plant would have both qualities to extend the season and be the best tasting in my opinion of course.
If only four trees, I would plant:
1. Rosigold - good flavor, consistent, dwarf and earliest.
2. Carrie - One of the best mangoes (if you like the flavor) , compact tree, good disease resistance.
3. Lemon Zest - Another of the best mangoes ever. Maybe the GOAT.
4. A late season would be difficult as there are not many choices. Keitt is good and very late and excellent producer. Although I would prefer a mango with a little more flavor. Neelam, not so sure about. I have never tasted one but read that many do not like it. I am intrigued by the new Cotton candy mango. Does anyone know if it is really a late season mango? What about flavor, tree growth and productivity? This is one I would consider, being from the mango powerhouse of Zill
Also, as to madame francis. I have a tree and its a very good flavored mango. But I am now a mango snob I think and I just can't get over the fiber. There are so many other excellent varities out there. Thinking about top working that one and also my Haden.
E.