Unique 2 fam w/ detached retail, zoned commercial

[James Nazario]

This is my first post, besides my member intro, and I'd like to share my first and current situation. I am due to close on my first property and wish I found this site before I even started looking. Not to say I'm feeling regret, but I'll explain:
I am purchasing a two family home renovated from a cape, with one 2 bdrm 1bath unit upstairs, one 2 bdrm 1 bath downstairs. There are separate entrances, stairs have been blocked off and is all legal. It has a total of 1450 sq ft and is dispersed almost equally between the two units. There is also a full walk out basement for laundry access and storage for both units. There are updates that need to be made but as a whole the house is in great shape. I plan on occupying the downstairs unit for the first 2-4 years and move on from there.
I have a three car garage plus a covered car port for parking. What makes this property interesting is the fact that it also has a small 250 sq ft detached retail space in front of the house. The property is zoned commercial retail and spans .47 acres.
I could not get a bank loan for this property- residential lenders wouldn't lend due to its commercial features and uniqueness, commercial lenders wanted to see proof of rental history and cash flow. The house was family owned since bought new in the 1930s and only had family living there so no rental paper trail is available. The seller agreed to hold the note for 15 years with five year resets, while I make all efforts to refinance through a lender as soon as possible. So the numbers are as follows:

Purchase price: 105,000
Loan amount: 90,000
Loan term: 15 yr with 5 yr resets
Interest: 3.5%(1-5)5.5%(6-10)9%(11-15)
P/I: 643.39(1-5) etc.
Annual taxes: 6,800
Annual insurance: ~1700
Total monthly pmt:~1,345

I anticipate rents anywhere from 700-850 for the two units and have no idea what to do about the retail space. Originally the family ran a memorial art service out of it. It is placed on a main road so it has plenty of exposure, I just don't know what businesses to address.
Just looking for some insight on the situation but my main question lies mostly with the retail space; who to advertise the small space to? Would it make more sense to remove it completely and eliminate $700 of excess insurance? Or do I build onto it(if the town allows) and have more rental options. Please let me know if I missed anything and I appreciate any and all responses! Thanks!

-James