If you think Marshall is clearly a greater bowler than Hadlee then I can definitely understand why you'd go Marshall here. I don't though so voted Hadlee. Also, I'm a big fan of Kallis but would definitely agree both of these are greater players than him.
As I said, Hadlee isn't a wrong answer, but to believe Marshall is automatically one because of lower order batting, when they both bat at 8, is one of the great mysteries of this site to me.
Hadlee scored two test hundreds, one against SL, and the other in the most contentiously umpired and contested match in history. Both were high scoring draws.
Of his fifties I found two that heavily contributed to victories, one of which on that contentious series vs WI, rest were mainly high scoring draws (6), losses (4) or a couple.matxhes where the opposition collapsed (one match England didn't pass 93 in either innings).
Even looking at his career vs India, he played 14 matches having 0 impact with the bat before scoring 87* in his final innings that improved his numbers.
Averaging 27 is a failed test batsman, and similarly Hadlee wasn't a consistent or reliable scorer. Lots of single digits and the odd score mostly in favorable conditions. It's not the reliable lower order scoring that's depicted by the comments and sentiments that's expressed.
If you have a poor team, a 30 odd lower order batting average isn't winning you games, or even saving that many. If you have a great team, it doesn't require the lower order to bail you out that often. I don't understand when we decided that bowling all-rounders were the alphas of the sport and we're critical to success or impactful.
This isn't about Hadlee by the way, he was a tremendous bowler, top tier ATG, but his batting didn't move the needle that we like to believe, just didn't.
What was ideal was any guy who wasn't a rabbit who could handle a bat and hold down an end when required, and so many of those innings were played by guys who didn't nearly fall into the "all rounder" category.