The squatter called the cops, the Landlord and his buddies showed the lease and confirmed their right to be there, the squatter had no evidence, and the police told them to leave, which they did.We shouldn't need attorneys and judges to kick out trespassers.

It depends on whether your local judicial system accepts email as evidence.

And if Tenant disagrees, I'll show them the lease and evidences.

In my mind I would say that it would be best to wait until I have more capital and then begin the BRRRR process, but I don't have any solid evidence other then gut instinct.

One has been saying that home values will continue to grow and there is not much evidence to prove that real estate is in a bubble.

I also take timestamped photos of it to used as future evidence.  

Unfortunately, it would be awfully hard to prove this without some evidence which would be hard to come by other than from a disgruntled or ex-employee

Any one of those should leave some evidence behind.Because the home was not the cause of the fire, you can hold the tenant accountable and charge them for the deposit.

I'd call the police, but if your tenant doesn't like the police, they aren't going to cooperate with them, so the police won't be able to do anything since there's no evidence...unless there was a witness,..or two.Having said that, you haven't mentioned the more important reasons to sell or continue to rent it out. 

I'd imagine you'll see evidence of his marriage on there.