Making a Protean/Forecast/weather summoning combo ability

[ICEDJaguar]

So i felt like Castform could do with an ability buff.

I was thinking something like:

Like a combination of Protean, weather ability (Drizzle,Drought etc.) and then Forecast.

So depending on the move selected; say for example blizzard is selected. The ability will be like protean changing Castform's type to Ice, the ability will then summon Hail and trigger the form change. Finally the move itself will be executed.

So the ability will only work with the types which have a connection to a weather move. Hail, Sandstorm, Rain Dance, Sunny Day.

I did have a quick look at Protean, Forecast and Drizzle but have no idea how to make it work and to do so in order.

Thanks in advance for any help provided.