Keep in mind, adding "cute", and upgrading things won't increase your rent or ARV past what the market in that area will tell you is the max. 

With your income, you may qualify for an FHA loan with a smaller down payment, but buying now could limit your borrowing power and increase monthly payments.

How much will the increased cashflow supplement your anticipated SSI?

Do you need to refinance quickly to avoid a balloon payment or other financial pressure?

Perhaps if your partner was a general contractor or handyman type there may be some merit there to reduce costs / increase profitability.If your partner enjoys deal sourcing, a better move might be for him to become an agent - so he could legally collect commissions from finding deals and managing properties for multiple people. 

If private companies continue to provide the insurance, I suspect we will see further increased premium costs which will need to be reflected in the rents tenants pay (all tenants: LTR, MTR, STR).  

If it’s doable financially I’d recommend the duplex.

That will show what proposed tax increase you will see.

Prioritize your financial stability.

Meet with financial advisers/wealth managers and see what other options other than real estate there are and how to best allocate / diversify. ie have you maxed out your TFSA?