re: New Construction Drainage Worry

The lot was improperly graded leaving the yard higher than the top of slab. Standing water against slab is very very bad. Especially if slab is a thin as it looks.

Your pics show a lower tree-covered area nearby. Go ahead and hire a landscape architect who does drainage more than layout gardens. Pay for their advice.

You'll need more that French drains (buried seepage lines). You could try buried 8" open lines, catch basins, and roof gutters feeding into the drains ( I did this). I do have a large parish ditch behind my lot.
.

Alternately and cheaper might be swales...shallow pathways dug into soil surface collecting water and directing it away from house...assuming there is a low ditch somewhere nearby.

Whatever you plan on doing, you need to be aware of property lines, servitudes, right of ways, impact on neighbors, etc.

Shop around more... look for hills.