Looking at a seller finance deal, I am also new. Would like some assistance or advice

[Jaden Vernon]

So, I'm looking at this seller finance deal and I understand maybe for someone new the best option is to not look as something so grand. However, It's a 16 plex listed for 1.5M near me. I have tried to learn about the process and may be missing some links but had tried to learn what I can. I went through my agent, who got in touch with the seller. and there terms are as follows, 

A 25% down 5% interest rate, 25 04 30 yr amortization with a 5 yr balloon payoff in full.

I do not have that kind of money to put down 25% on a 1.5M some. So I thought about trying to negotiate. Seeing if i could do something like a 1.65M with 5% interest, preferably close as i can to a 0% down. 40yr amortization with the same 5 yr balloon payoff. But im thinking that adding 150k to the total would likely not be enticing enough as a offer for someone to trade 25% down on. to get an extra 150k on the loan sum. Of course with the included benefit of not being taxed the large downpayment sum. (If I'm thinking about that right)

I appreciate any info I can get. Thank you.