It's very unlikely a Court would see a scheme of arrangement as necessary given the requirement to have the agreement of 75% of the shares not held by the bidder for the scheme to be approved.
If Moshiri approached the court already owning or having the right of ownership to 75% (approx) the court (in fact his own lawyers prior to approach in the court) would point out that 90% is a lower threshold than 75% plus 75% of the remaining 25%.
If we ignore his options agreement and just look at his existing holdings (I'm not sure we can ignore the options agreeement but for the purposes of this, in theory) the threshold by going via a scheme of arrangement drops slightly to 87.5%.