Pathfinder 1x: Needing to upscale a dungeon


ok, Have an old module I’m revamping. Using original pathfinder, home brew world. I have no drow or underdark, but an ancient evil locked away which leaks its creations on the world. (predominately father-god of all goblin kind (which here will include orcs, trolls, etc) and all things demonic and abberant)

What I have is an empty dwarven fortress with what is basically a goblin town below it (unaware of the dwarven fortress above as its been empty for 300 years,…well of dwarves anyway, so no actual goblinkind can be used). The module has a tribe of Grimlocks who have moved in with their dire rat pets. Problem is, by the time the PCs made it to the module site, they’re 7th level. (silly me, I gave them a ghost town to tackle on the way). I can probably upscale the grimlocks, maybe with bugbears or something similar (will still take suggestions) but I’m stumped on their ‘pets’. Dire rats are just too weak for this group, and I think they could take a swarm easy (though the ecology wouldn’t necessarily feed a swarm). I either need a substitute critter that is a good monster pet that has the ‘bite’ to take 7th level party of 4, or suggestions on how to build them as ‘giant’ dire rats and put some meat on them.