I hear that seller financing is a popular strategy to acquiring an asset without the conventional lending.

No local bank is MA will lend less than 25% on investment.   

Your credit score will help - Lenders don't want to lend to owners with history of bad debt, etc.  

Here’s where I need the advice...I’ve got 25% of the cost to rehab, but would any institution agree to lend money on a property I don’t own?

talk to Peak Asset Lending in KC  @Alexander Felice  banks generally wont fool with stuff this low unless you have existing relationships with them.. the cost and risk of having a default far out weight what a bank can make on a 15 to 20k mortgage.but i have seen small local commerial banks do these for local citizens that own 10 to 50 homes and its their cottage industry so to speak

Now those homes will go to investors and used as rentals as you would be a fool to lend based on those terms.

I recently had issues finding financing at an 80% LTV (i.e. 20% down), most banks wanted to lend at 75% LTV (25% down), but I called numerous banks (probably around 10-15) till I found one who would give me 20% down.

I am currently trying to buy another single family but I would like longer-term and was told by my  financial institution that it was not possible if purchase with my LLC.

If he wants to lend more money send him my way!

What my insurance agent is saying makes more sense because why would a bank require you to have coverage beyond the amount they are lending you?