Jordan, I feel for you, we dealt with this last year. Had a bat in the garage and it was about 28 degrees outside, had to come from the attic. We paid a company to come in and do the exclusion, cost right around $1,000 from start to finish. Had a very small colony, as we caught it right away, and the technician identified 2 species of bats. They sealed the house in mid-January and put a tube in the entrance/exit until April and then sealed up the final entrance.
Never had any problems with them getting in the house. Drew, the bat guy, said if the temp slightly warms they may go in search of water or they might climb deeper into the wall if the temps get colder. If a bat happened to get in the house generally they will not bite. If the bat happens to make it into the bed covers, which is not likely, they may bite as you role around. The only case where he had ever heard of a person being bit was in a basement where a bat had gotten into a pile of clothes and a gentleman received a bite when he picked up the pile. He had completed hundreds of bat exclusions and said rarely did he find bats inside the main living area, especially during winter.
Like you, I was initially worried about them gaining access to the house. I have 4 kids and the last thing I need is a bat in the house but never had any issues. It was a very uneventful process and the wildlife company was great. Good luck and I wouldn't worry too much.
Notes: I am in Ohio, so take the information based on location. Second, we didn't tell the kids until after they closed the final hole, I like my sleep.
