You are going to need to type these folder descriptions anyway, correct? It makes no difference AFAICT whether that's done before or after import.
My suggestion would be: let LR import the two sets of pictures using an automatic date-based setup. It is possible to customise the naming structure, but IMO easiest to just accommodate yourself to one of the provided ones. This can be left to complete itself quickly and error-free - because minimal interaction is required.
Then as/when you see the need, rename these two folders inside LR's Library module, after import - as part of your organisational stage for these images - appending your description to LR's simple date-based names.
I personally would be more likely to give the two sets of pictures "mybigreddog" and "mybigfluffycat" keywords etc, and/or, to add them to suitable Collections... and leave the physical folder system as auto-created. But that's completely a question of preference; one might as well make use of LR's folder automation either way.