hi,, ive done lots of these,, but first you need to get some chichen wire crunch that up into a ball wedge this in the holes make sure its 5mm back from the surface then inject the foam allow the foam to go through and come out the hole.. the wire stops the mice from noring through the foam then decorate ,,,,

never use foam as the mice will eat there way throught it try cement before they get through the cement there teeth will have worn down :)

no.you need to bed a brick into the hole .then use one coat bonding to smooth of excess..rats or mice will eat the foam when it hardens.

ive done alot of these as i used to do pub refits. mice will eat through wire. you dont need a mask and goggles. a mouse can fit through a hole the diameter of a bic pen. get yourself some gaffer tape put this over the hole then make a little hole in the top quarter of the tape put the can spout in the hole and spray make sure you wear gloves. its a sod to get of you. when dryed pill the tape off and wow. one perfect filled hole..roy

AVOID EXPANDING FOAM if you can, it's an absolute pain to remove if it ends up where it shouldn't... and it will ;)
If the holes are small enough, use silicone or point them with sand and cement.