1) what size round bases do tzeentch flamers + mounted daemonettes go on?

2) what would be a good stand in for the bloodthirster? im thinking galrauch or would it be too big?

3)would dark elf harpies fit into a slaanesh daemon force as furies?

4) any other ideas for a tzeentch / slaanesh daemon army? like which daemon prince to use?