Perhaps I'm reading something wrong here, so correct me if I'm wrong.
My general impression upon the numbers you provided at first had me thinking that you need to have bigger profit numbers for this to be really worth it. It's your first deal so I understand things aren't going to be perfect.
Then I read about five paragraphs into the inspection stage, and I started to get kind of worried for you because I think you might've overpaid on this property tremendously without realizing it. I didn't even want to read the rest in-depth so I scanned it.
When a property is in need of very serious rehab and repair like this one, and you plan on flipping it, you need to make the numbers make sense. A great flip would've been if you had gotten the property for a ridiculous deal, because the deal just has to be like that to be very workable. This might slightly shock you, but I believe you overpaid by about 80% more than what you really should have paid. I think a purchase price of $50,000 would've made more sense and would've given you the necessary cushion to make what you really should make. I hope things turn out well for you and you at least make $5,000 in profit from the flip.
The problem with major structural problems is that when you sell it, the next potential buyer who previews your property will think "this structure has had structural issues, and it has been fixed. however, there is a similar equivalent property nearby selling for the same $145,000, and it has never had major structural issues that needed to be remedied. why should i buy yours?". And the problem of the issue could potentially arise again even though it's been fixed.
By the end of the day, I take a step back and ask myself, did the buyer win here, or did the seller win? I believe the seller has won in this situation by more than a small margin. He had a property in obviously terrible shape, and was able to sell it for more than just pennies. He's probably pretty happy with the sale right now because he knows how much it would really cost him to fix it (or perhaps he doesn't have a good clue). At under $50,000, I would say that you guys have the upper hand, and it's all about having the upper hand in every deal.
When rehabbing properties such as this, the main objective is to buy them for pennies on the dollar. Even lower than $50,000 would've been great, even if the owner would've had a 99.9% chance of rejecting it. You just gotta walk away from that deal. The owner is also kind of silly for listing his distressed property for basically $149,000 which is $5,000 above your ARV. I hope your ARV was excessively conservative because then this deal at least would make more sense.
Please keep us updated and tell us how things go. This is an exciting thread.