ask your lawyer if u dont have one or they don't know find a better one. They'll probably wanna settle for a lot less especially once u get an attorney
Whether you knew about the code violations or not, you rented the home to these people and then had to kick them out. That's not their fault and you owe them for the inconvenience.
$30,000 is ridiculous and unjustifiable. The cost of hiring a professional mover would be around $3,000 depending on family size. They had to rent a hotel room and eat out for a few days. All told, they are probably out less than $5,000 which could be settled in Small Claims instead of hiring an attorney. Did they even try to contact you directly and ask for assistance with their moving expenses or did they just go straight to hiring an attorney?
I would not hire an attorney yet. I would write them and explain the situation, apologize for the inconvenience, and offer to pay their moving expenses. However, I would require receipts for everything. If they moved themselves, I would contact a local moving company and ask for a rough bid to move a family of this size or a household of your size and then offer that amount to the tenants.
Try to deal with them directly and nip this in the bud. If they refuse, document everything and find an attorney.
Hire a lawyer who's advice you think you will trust, if you after hearing the lawyers advice you don't trust the lawyers advice, fire the lawyer and attempt to hire a lawyer whose advice you will trust.