If I was not starting from scratch, like I did myself, I would buy SFHs because I prefer their long-term flexibility, relative scarcity, and multiple exit strategies to MFH.

May negative cashflow until fixed.3) Buy established business: assuming you mean something other than real estate related.

Debt is rarely a factor in their issue. the ultra wealthy I know  with a few exceptions have very limited debt.. to no debt. 

What can I expect for timeline, potential issues, rough costs? 

If it's rehabbed nicely, then you will no issues finding a tenant.

First time using a contractor to fix a few issues at my property before putting it in the market.

The IRS views this as a related-party transaction, and deductions like rent paid to yourself wouldn’t qualify.

Meanwhile, the sellers who are most likely to offer creative financing are normally the owners of  real estate that have issues.....condition.....low barrier/over supply market......or perhaps pricing issue, and one of these factors is why its not marketable in a arms length transaction and why creative financing would be accepted.

Covering the mortgage isn’t an issue, but I’m considering factors like: Multi-Family: House hacking would help offset costs right away, but I’d likely need to put money into renovations upfront.Single-Family: Easier move-in with no immediate renovations needed, plus potentially lower tenant turnover once I rent it out For those who have been in a similar situation, what did you choose and why?

For the most part, most lenders are going to be relatively close in cost assuming we are talking about a straight forward loan product, we all borrower from the same pool of money to make these loans.