Happy to provide you with averages for vacancy, what I use for maintenance, taxes, insurance and can even send you some videos on how to best estimate rent rate here haha! 

I have a PM a little above average and they need to be managed. 

I think that the main recreation season is only about 6 months so I would like to figure 50% occupancy to be safe which means $30000 per month on average for STR .

How long does the average tenant live in a unit?

I would error on the side of caution and just go with what the report says about their background unless they can provide compelling evidence against it.Both your applicants seem like typical renters and both have credit scores higher than my average renter. 

On average, how quickly does it take folks to find a deal and get an offer accepted?

The PUC does not always read the meter-they do averaging for a number of months and 'catch up' in a month where they actually read the meter; that is very likely the case.

Get three bids for each trade and average the pricing per SF.

Average tenant stays around 3 years, so if you're guessing 5% for vacancy, you're factoring in 2 months between tenants.

Just know it's 75% of the gross rents OR a 1 or 2 year average of your Schedule E (rental income in your tax returns) after accounting for 75% of gross rents.