I'm sorry you are dealing with this. In addition to being and investor I own a restoration company that specializes in fire damage, so we help you with a lot of weird situations like this. I'm glad to hear you have a professional company to remediate.
A few observations: Both @Joe Splitrock and @John Underwood are onto something--getting them out is the right away is the thing to do. With all due respect to Joe, it is a huge mistake IMO to let them stay--too much liability and health and safety risk (they really should not even be in there without masks) involved and will massively slow down your remediation and repair process.
If there is potential damage to the electrical system, there is reason to shut off the power if it is not already off. This action may "force their hand." In normal circumstances it is not legal to shut off the power to force out a tenant but if it can be demonstrated that you must do so for safety, then that changes the equation (although I would consult an attorney before taking that step--I'm not an attorney and don't know the laws of your state. Besides, you want someone to have your back if things go sideways.).
Beside that--code enforcement or some sort of expedited process would be much preferable to the whole eviction process--go through the eviction process if you need to but I would try to do it faster than that.
I understand both the investor/owner side as well as the restoration perspective, so if you need any advice or have any questions I can answer as you go through this process, feel free to reach out. Again, I'm sorry you are dealing with this, but you will grow as an investor through it.