I would generally recommend starting w/ househacking where you live but understandably for some, that may not be feasible for various reasons. 

Managing one property as well as a W2 is definitely feasible if you keep an organized book of your rents vs. any and all expenses.

I don't think something like that would be feasible for most with one or two properties.

But understandably for some, that may not be feasible for various reasons. 

Would you say that this is feasible or is there another funding route I should take?

I would generally recommend starting w/ househacking where you live but understandably for some, that may not be feasible for various reasons.

It's not as ideal, but it's still feasible and helps with mortgage payments.

Could consider converting it to a Short/medium term rental, depending if that's feasible in your market and could generate more income. 

The land does not do you much good in its current state so something needs to be done.I do not know what the land is worth or how feasible building would be, but if you can build it, it is likely that you would have some equity in the duplex when it is all said and done.

BRRRR is ideal for MF if the rehab is financially feasible.