Okay, I am going to put this as succinctly as humanly possible for you to best understand how both Caja and Nemo do desktop icons.
xfdesktop4 does icon arrangement similarly to Microsoft Windows, where icons are not allowed to overlap one another.
Nemo and Caja, being derived from Nautilus inherited the “Fine mesh” grid that both file managers use.
What you seem to be looking for is a grate that puts all the marbles in their place, which Nemo and Caja isn’t. They’re more like sieves in regard to their icon placement; They do snap in place, but it’s very fine in comparison to the marbles in grate holes that is both Windows’ Explorer and XFCE’s xfdesktop.
I do like how useful xfdesktop can be, hence why I wrote a guide about using it (despite if thunar isn’t installed, desktop file operations are broken) but despite that, I like the consistency I receive with letting nemo handle my desktop, in comparison to using exo-utils to open up my file manager, having mismatched file managers and lack of folder colours, which costales’ PPA for that provides me.