Am in a similar position, but my plan is completely different that yours. I too am eligible today, but will hold off until I can submit my tax 2018 and then apply by mid Mar or so
Yes, as per the application you can mark it as Yes to lodged (as by the time they process it, you would have applied it by then anyways)
But in case something comes up (some complications with tax,personal situation etc and you are not able to lodge it), then your CIC application would still say Lodged. But you may have not actually lodged.
CIC may return it back saying, incorrect/incomplete information. And you lose few months for it.
So I rather wait, submit my tax first and then apply a complete package in peace (losing one month in process vs many). This is my thought process only. You may or may not choose to follow it.