yes I am sure that would be Ok- it's all compostable, and in fact a bit of soil/compost will help the process.
But you are quite right - your concierge is certainly much more likely to know the answer than anybody on this here forum, lol.

Many people fail and give up with composting as they just put cut grass in it, and it just turns into a slimey mess. Layers is the key- I use wet corrugated cardboard between each lawn mowing and it works really well.