Praise the Lord - we have squirrels (and rats)! I felt that we should really look into someone else to come see the house as I didn't want the animals to die in the attic after eating the poison. Just wasn't feeling great about it. I looked up "rat exterminator" online and came across an article by A Wildlife Pro. Sounded like great tips and found that they are located in Plano. Gave them a call and the guy came out two days ago.
He demonstrated sounds of animals with his hands on the wall to see what sounds we had heard. He immediately said "You don't have mice - you've got squirrels." I was like "Sweet - I'll take that!" He checked outside and couldn't find anything that showed where animals would be getting in. Until he looked on the left side of the porch where the wood meets the brick. Turns out that a brick had fallen in and that it had left a huge gap large enough for just about any animal to get in.
I asked him to check the attic for my piece of mind and he said that he could see some small rat droppings showing that they'd been up there at some point, but that he could clearly see squirrel poop and a paw print on some piping. We still have rats in our garage (not mice) but everything is being taken care of.
He assured us that it wasn't an unbelievably bad situation - it was very normal and not a big deal. He said that they're looking for warmth and that their ecosystem was badly disturbed causing them to look for a place to go.
We'll be having a few things done soon to prevent the animals from coming in and can then do some clean-up to get it restored to normal.
Not excited about rats, but SOO glad all the noise we heard upstairs was a squirrel. Scratcher the squirrel is so much better than Scratcher the rat.