It looks like a great start to a crematorian’s list. My guess is that you want to make use of the MW from exploding mortek guard and use the harvesters/arkhan to regen models?
if so, imo I think Arkhan is too much for healing/spell casting; two harvesters places between the three 20 man units evenly and a Boneshaper would be a better option. You can also add a Shrieker endless spell for the +1 to hit. That would give you room to give your Kavalos the Searing Blade, allowing your Soulmason to take the Gothizzar Cartouche for +1 to wound, making your front line +1 to hit and wound.
This would leave you with 200 points to spare, giving some flexibility on what to add.