There really is no quick and dirty formula to use as it varys house to house but an experience investor agent should be able to tell whether it's worth your time or not. 

You have to set up a US entity (usually an LLC but may vary depending on your country....like Canada isn't an LLC it's another weird acronym (I forget what)) and a US bank account.

Material costs can vary greatly depending on manafacturer so it's hard to say but you could get a decent no pattern low pile carpet and pad combo for between 10 and 13 per SY. 

It varies, but in many parts of the country property taxes are 1-2% of the purchase price.

It's about 30 degrees above normal. 

This sort of thing varies from state to state, but you likely will not be able to charge an arbitrary lease termination fee if it's not spelled out in the lease. 

Texas has a lot of weird laws most other states do not follow.You're right, laws do vary by state, but if you win a judgement, they are usually on your side.

It could vary from relatives info, historical addresses, social media activity, past phone/email addresses, ect.

Splits vary per deal and per situation but 50% - 70% going to partners is typical.We are regulated to death and it is only getting worse, most of which is a claim to protect consumers, I don't see how that is true, but that is just opinion.I still stand firm on my belief that having the ability to pay all involved so that nobody other than you loses money is key.

The amount a tenant will ask for varies greatly all over the city.