Thank you so much! <3
The RTP Replacement pack for MV/MZ's iconset is only free non-commercially because a commercial license requires purchase/ownership of the packs. So they can totally be used commercially as well, as long as you have the pack that the icons came from.
These tiles are free for commercial and non-commercial use, with the exception of using RPG Maker characters outside of RM. Other than that, they're all good to use! :D