Starting to reasearch/setup questions

[Moosea]

I bought a fluval sea 24g all in one system used with all equipement. I have been reading and reading to learn about reef systems. I have kept planted aquariums for years. I have a few questions.....
1-the 24in led light will it grow softies and seaweed? Fluval redsea.
2-How many water changes are needed? On my fresh water i do one once a month. In the beginning i did many until i realized it was not needed. Is this true for reefs?
3-what do you do for holidays?
4-using used live rock speed up the cyclinging? Can i put in zoas, i was told yes but i think a 30day cycle better for me..
5-I live in the interior of bc and it gets really hot in the summer will all my softies die? My fresh water sometimes at 31c.
Thanks for all the help in advance.