Mains Low-Glare Wetroom Downlight - White or Black IP65

Does fire rated mean the same thing as IC rated so that these can be used safely under loft insulation?
While IC-rated lights are constructed to avoid starting fires, “fire rated” lights and covers serve as a fire barrier in the event a fire has already started.

What length of bulb will these lamps take? For example, will they take your Elite HD LED CCT and colour changing lamp?
This product is compatible with most smart light bulbs, including Philips Hue. There is some flexibility with the lampholder.

Are these fire rated ?
These are not fire-rated.

Just wanted to check if this light fitting is fire rated?
This fixture has not been submitted for fire testing. You could use a Fire Hood if you believe you require a fire-rated installation.

Could these lights be used on the underside of an out door soffit board or the underside of an outdoor porch roof ?
The high IP rating is between the bezel and the ceiling or board . As long as water cannot enter the void it will do everything you need.