You can put lakes anywhere you think you want them / they ought to be. The color image from the other thread with the green-blue was showing where sea level was tho. The contours show that there are many basins in the native data. You don't even have to follow them rigorously as that might lead to lots of little lakes. At this later stage in Ansium, not a great deal matters apart from some modest level of continuity to your neighbors.

Here is the tile with native data in 3D if that helps. You might decide to munge it about a bit first. The creator of FT recommends to do it and I did it on my tile. Its up to you tho. Nobody is making any attempt to be strictly continuous with neighbors in 3D or small detail height.