Its not Good Idea to use helicopter for CAS in see because there is no place to hide and operating helicopter relay heavily on that , the helicopter if appropriately armed is good against small boat , but a question who except IRGC use helicopter in this nook of the wood ? Somalia pirates ? will shahid Soleymani corvete ever be used against them ?
helicopter can be used in anti submarine warfare , yes but a better use for them is countering sea mines .
search and rescue is a valid use for helicopters , but will it be part of the mission for this ship ? you must ask it from IRGC , that role is usually part of coastal guard duties
Anti ship warfare , i seriously suggest don't do that unless its against smaller one that don't have potent air defense or sonar
Reconnaissance and surveillance, well i can understand it in case of capital ships (perhaps its a capital ship for IRGC) then that make sense specially they are building smaller ones called Shahid Mohandess which have no helicopter nut twice missile . and if i recall correctly they want to build 2 of those type for each of this type . so that one probably provide the main anti surface capability and this one provide air defense and what helicopters are supposed to do.