My feeble mind is having trouble figuring out the best way to pay for it all.

@Sanil Subhash Chandra BoseRecommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a Class A property in Class D area, what quality of tenant will you get?

Not to mention trying to figure all of this our on your own.

I plan to to rent it for 3500 when the time comes (first floor with basement)We are currently looking for our next multi family but just need to figure out the best route forward for financing the purchase.Use our own money, tap into the equity here, refinance here out of our FHA to roll into another one at our new property, go the Fanny Mae route with the 5% down Multi Family home loan program. 

Otherwise, as @Nathan Gesner points out, it can be MORE expensive than hiring the right professional.ALSO:Recommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a Class A property in Class D area, what quality of tenant will you get?

Given my tech and data background, I'm considering developing an online app specifically for Canadian investors.I'm envisioning an interactive dashboard that integrates economic data, sales figures, bylaws, and rental information, complete with prediction models.

I recommend he look for a property manager who can figure this out and stop the bleeding, then maybe take over management in a year or two when he's better prepared.

Its a means to an end, letting you get settled and figure out the area before you purchase. 

You should be able to figure out your future non-homestead taxes by looking at your current tax bill.

I haven't quite figured out if its possible to transfer certain licenses to certain states if you are a real estate agent or broker.