Hi all, Im a newbie and need a little help with some calculations

[Kasey Blow]

I am looking to buy a SFH as a long term rental and my back up strategy is to short term lease it/airbnb it. I found a property on a super busy street in Lincoln NE that has been 100% rehabbed by the current owner looking to sell it with owner financing. Their terms are purchase price of $199,000, $5000 down payment (which I have no problem), remaining balance to be carried at 5% for "a while" they say, a monthly payment to them of $1,080, plus half of insurance and taxes to be paid by me which the owner figures is about $300 a month plus all utilities on me. Owner later says to me after I havent responded to their text message after 4 hours because Im running calculations, "terms of the contract can be somewhat negotiable".

After calculating for a long term rental I found that only having to pay above mentioned figures minus all utilities except for trash monthly ($25/mo avg for my area) I would have to rent this 4 bed 2 bath 2,044 SF home for $1500 a month minimum to not CF negatively and I would have no cushion to drop price of rent was too high in order to rent it out. My concern is that I am unsure if I can actually get that amount of rent for this property due to the busy street. Zillow always seems to be on the higher side of estimating potential rents to me, or are they pretty spot on? I have ran out of free calculations on rentometer which seemed more accurate. 

I then re calculated the numbers for a short term rental and charging $150 a night fee with 50% monthly occupancy and all utilities being paid (est.300/mo), plus the $1,080/mo to the owner,  plus the airbnb website fee of 3%/yr/mo (if I listed it on there), my half of the annual property taxes and insurance to the owner of $3,600/yr, plus $150/mo for cable and no management fees as I will be self managing. Turned out to make me significantly more money than a long term rental around $1,200 + a month. (long term rental calculated around $65/mo CF). Now Im wondering if the property would actually be a successful short term rental, if I could actually get 50% monthly occupancy. (also have good amount of $ to fully furnish the house). House is within walking distance to the zoo and local garden, a 5 minute drive to downtown stadium, bars, university and event arena. Seems like the short term rental is the way to go if I want to move forward on the property but am hesitating as we are going into winter and most of these local attractions go dormant quite a bit due to NE cold winter months.

Would love any advice on if using this property as a short term rental in my area could be successful despite a good 4 super cold months where people dont frequent these attractions as much?      If my calculations seem correct based on the owners terms?     What good tools/programs/websites/calculators others use to make long term and short term rental analysis?      What other terms could I counter back at the seller with to make it a better deal for me?