If I am all in on the property for 360k (purchase and some finishing construction as well as carry costs) and the home is valued at 450k or more (based on what im told by agents as well as my own analysis while staying conservative), that is 20%+ equity I believe, unless I am missing something.

You are missing the point.

Like you said , anyone can check the history,  I do have cameras installed and I do check twice weekly, it's not too far from my primary home . im a first time investor, is it ok to DM the listing to see if I'm missing something?  

Or will I miss out on writing off some of the expenses?

You’re spot-on about the "missing middle."

When I do it at 20% down, I can only find negative cashflow, so I could be looking in the wrong spot, or I need to put more down, or I am missing something all together.I have read that making a 8% return or higher is what to look for, and I can find break even.

We hear less BPRE episodes featuring individual investors, and it missing the breadth of STR and LTR knowledge that David Green and Rob brought into the discussion with the guests. 

Nothing will piss off the inspector faster than missing an inspection.My last piece of advice, in an effort to not make this a book length post, deals with the money.

A double-entry system (like QuickBooks) allows you to reconcile your bank statements, ensuring no missing or duplicate transactions.

Meaning that if you fund a $5K EMD and then decide not to close you lose the EMD, or you pay for an inspection up front and risk missing out on the deal while you're waiting for the report.