My thought that is if I take out a traditional loan it still hits my DTI where as hard money wouldn't. 

It doesn't have to be the traditional live in one unit and rent other out multi-family.

That is the standard list of documents required by all banks if you are using a traditional loan. 

Most banks and traditional mortgages "Do not" allow foe the property to be vested or quit claimed into an LLC unless it specifically states it on the closing disclosures.In most cases even on DSCR loans the Bank/Lender still requires you to sing a personal guarantee even if they allow the loan to be vested into the LLC.  

You can't combine Roth and Traditional money in one account unless you do a Roth conversion, which would be a taxable event.There is no one-size-fits-all when it comes to investing using your retirement funds, but you certainly can own rentals with leverage in an IRA and this can be very profitable. 

Conversely, the same two-bedroom, one-bath unit could fetch $1600-1700 under a traditional LTR arrangement without furnishing or utilities.Considering the added expenses, the MTR/STR model doesn't seem worth it for me, given the marginal increase in revenue.

For one thing, a traditional property manager is not likely to want to manage your property in a rent-by-room scenario.

Assess your financial situation and consider financing options such as traditional loans, private lenders, or partnerships.

I would like your opinion on whether it would be better than finance the whole purchase with a HELOC from my primary residence or only get the down payment from there and get a traditional mortgage for the rest. 

I am in an area that traditionally makes guests bring EVERYTHING I just mentioned in both paragraphs above, including sheets and towels, so they are happy with what I provide.