GENERAL KNOWLEDGE: Four wheeled enclosed carriage?

Questions

Exploitation of slum tenants by unscrupulous landlords, named after a landlord of the early 1960s in London?

A million raised to fifth power?

Sarcastic remark, clever saying?

Five objects set out so four are at corners of square or rectangle and the other at its centre?

Hard acid yellowish pear shaped fruit used as a preserve or as a flavouring?