H995 4 in. Aluminum LED Recessed Lighting Housing for New Construction Ceiling, T24, IC Rated, Air-Tite (6-Pack)

Only way to access the junction box after it’s hung would be if you have access to the ceiling above like an attic. If you need this access, there are other types of cans, but this one would not fit your needs.

You can pull the sleeve that the light fixture goes into out of the housing. Then access the box from the inside of the larger outer box.

You need a recessed trim, which will include an LED bulb built in. 4 inch trims fit this housing. You do not purchase a bulb for it, the bulb is included in the LED trim along with the ballast. AS for 2700K, LED color temperature is a personal preference. 2700K will match incandescent pretty closely, personally I like a bit whiter/bluer and go with 3000K but any color will work: some trims even allow adjustment from 2700K to 6000K using a switch.

Nothing. There are built-in cable crimps in the boxes, and the wire connections are provided using push-in holes for up to three wires. You DO need to by the lights, of course. 4 " Halo LEDs are what I used.

Yes dependent upon your specific lumens needs . Dim-able bulbs with a controller make that somewhat easier and more forgiving . Make sure You get a high enough rated fixture so You can UP the Bulb Wattage if necessary . IE ; Don't buy a 10 watt rated fixture and expect it to carry a 75 watt bulb !...

no, it does not have the screw in housing, it only has the cable to plug in the LED retrofit units

Yes. Those are what I installed.

No, the included lamp connector is only rated or 120VAC

T24 is referring to the Title 24 Energy Code, meaning this light fixture complies with the energy code. This fixture uses any Halo 4" LED Module, just plug the orange connectors together (they provide the medium screw base for retro fit solutions). The modules look to be about $30.

This recessed housing is damp-location rated and wet-location rated when used with select wet-location rated trims. It is also rated for direct contact with insulation. It can be placed in a soffit or eave if it is an enclosed area.