if you can see the holes they are coming threw,use steel wool to block the holes,they cannot chew threw it ,ive used it in house before while remodling them,
spinosad might do the job but it is costly for what you intend to do,it aint gonna fix it with one application, something i use in my garden for outside critters mainly coons and porcupines,is mexican food i call it,i light um up with every kind pepper the store sales,take every hot pepper you can get hold of also garlic and onion ,boil it down for a while until you have a really good broth ,when i make mine about the time the wife says what are you doing is when i pull it from the stove hahahah,but the let it cool and put it in a spray bottle and go to town on them,be aware it will run them off,you will see the spiders running no joke,but they will come back.
if you baby is of age to know better and stay away from the borac id go that route if they are as bad as you say,just use a spoon and make a line against the wall and cabinet edges all around every wall ,then spray, you should be able to buy anything with lye in it will do,they cant stand the smell for long ,this even hold coach roaches at bay. borax soap is good ,but i prefer the real deal when im messing with them , i had a a house in the city i was remodling and had rats bigger than cats,had a couple steel rat traps the just took off with,guess they went to the lake to party hahah so i had to tether the damn traps ,they wouldnt come in house or attic after the acid treatment,dang neighbors would set food out for the feral cats ,but the cats ate the food instead of the rats lol.
believe me i understood why when i got a rat that even with the trap snapped on it neck i still had to kill and these traps sale on amazon ,they have teeth around edge of trap and that sucker was still alive trying to break the tether .
i really hate to be the one to tell you your fighting a losing battle,but if the neighbors dont get on board with the eradication the rats will win