This is really impressive I must say thats why I thought I might try to help with some input on this base system, so firstly great work 
Now the first issue that I saw was the fact that there are fixed east/west type biomes, now if I were to do something like this myself I would try to make it more procedural and randomized in that it could support different types of land masses and not just continents but ofcoarse its possible this base system could be expanded upon.
Which leads me into the next point, whilst this system might work well currently I do think it could be made more adaptable, a primary example is how the entire pole sections are pretty much solid with no actual depth to their shapes.
The way I would have approached this is probably similar but I would have generated an entire set of blank tiles first, these tiles would have held an enumerator to their location in comparison to the equator, this would have been assigned mathematically when the initial two dimensional array (grid) was generated. As you can see on your generated table you can see the pattern it makes so you dont actually need to generate that because you know 5/15/25 etc are close to the equator at a height of 10.
In terms of the tiles and what type of tile they are I would do that within the tile itself and do something of a growth algorithm by checking the nearest neighbors to a select depth, this allows creation of land masses, peaks and beaches where you would expect. Ofcoarse there is always rivers and inland lakes but these can be taken care of as well, I would give tiles a height so Id know that taller peaks would also be snow like the poles so it might even lead to a more three dimensional array.
Im really curious about these biome placers, do you really place each tile in random order rather than just switching their “theme”?