I know it's off-season right now, but this feels way too low.I guess my questions are:1) how long do units usually sit on the market without getting rented out this time of year?

Plan is to reinvest most of the profits for 2-5 years before I quit my W2, go into real estate full-time, and live off the profits while continuing to invest. 

Is the 'Days on Zillow' counted although the listing off-market for a couple of days ?

I am also a real estate agent and was able to collect commission on the off market deal.

Sounds like you are getting a HELOC against your house, use proceeds to pay off the loans on the rentals, then get lines of credit against the rentals?

You don't want to add insult to injury by offering to buy their house off the bat including offering to do a Subto. 

The number usually varies from 10-20% depending on credit score, property analysis, etc.Some lenders will work with any level of investor experience, credit scores as low as 660 and can close in as little as 10 days (there are loan options for 640-660 credit scores- they require 20% down).Another good thing is interest only and 6-24 month loan terms- you can refinance by selling or refinancing to a long term DSCR rental property loan at any time once you complete the rehab.Once the property is ready you can sell it or if you want to keep the property as a long term investment, you can underwrite the loan based on your income /debt to income (DTI) ratios or you can go the DSCR route where the loan is underwritten based on the actual or market rents from the appraisal.DSCR loans won't use your income to underwrite the loan.DSCR loans are based off of down payment, credit score and either actual or market rents so it helps to supercharge an investor's real estate goals and net worth.Here's a bit more in detail about how rates are calculated for DSCR loans:1.

From most OOS investors I am speaking to this is where most of the attention is, so be prepared for competition - seems that this forum was revived from the dead but to answer the original question with a few practices you can manage the air-bnb yourself to get higher occupancy, I would recommend educating yourself on tricks for the platform those will make the biggest difference - definitely helps having someone take care of your air-bnb account and for completely hands off investing do that but just previewing/welcoming who comes in can be done remotely in a professional manner I have seen it done in multiple states. 

3) Would it be better to buy something off-market and fix whatever is needed or buying new construction? 

I have been trying to find properties in the Rochester, NY area off and on for the last 2-3 years.