1. In order for the floors to match, the aspect ratio needs to be the same?
I am not sure what is meant by that
It 'doesn't' but of course it looks visually best when it does.
It means the aspect ratio of texture and floor tile should be identical or at least similar. If you have for example texture that is 100 x 20 cm wood plank (ratio 5:1), you should be creating your floor planks with generator in same dimensions (100 x 20 cm) to look the same as in reality, or at least in same ratio (5:1 so maybe 120 x 24 cm, or 150 x 30 cm) so they don't stretch.
2. In vray there was a map called multitexture but I can't seem to find a similar thing for Corona as to mapping each floor board with a different texture
Multitexture is not Vray's map, but comes as free plugin from same source as Floorgenerator, CG-Source.com
https://cg-source.com/multitexture.phpThe map is perfectly usable in Corona as well. There is also native Corona's equivalent of it, but I think the plugin is far superior in user controls and ease of use.