A bit late to this but can confirm sleeping with her and then killing her does not affect other romances. In my Dark Urge playthrough I did this and then got with Lae'zel later.

There are other issues which come with artificial lawns too:

A friend of mine has an artificial lawn and hot ash from her neighbours' barbeques has made holes in it.

And my nextdoor neighbours have a cheap artificial lawn that now has weeds growing through it.