I am not fully convinced on  such 3rd party software  Fair enough, have you had any luck with software which you are manually uploading transactions?

But I'm trying to work it out in my head how I can ensure I don't walk into a mess.

The thing I am noticing though, is that these properties are still being bought by others in the area, fairly quickly, close to asking price.

I've read hundreds of these and often have to call the agent for an explanation to ensure we're protected. 

In those cases I had to approach the seller directly to ensure clear communication.

So, to ensure you can keep on renting our your spare room without the possibility of being sued by your tenant should your dog bite him or her, the only way to mitigate your risk is to have the tenant indemnify you by signing the addendum. 

If they are VERY professional, they will have their processes in writing as verification that it is enforced equally and fairly by their entire staff. 6.

For example, would the below fair/standard?

If you want to ensure that the tenant maintains a policy year over year, you would do best to have a new lease agreement each year with the same insurance requirement. 

I have a friend that has a fair share of liquid assets and he continually makes comments that he would love to invest in my first house flip.