My basement bathroom ceiling is very low (7ft), especially over the shower/tub area. As a result, I am installing ceramic tile on the ceiling because of the moisture thing. I'm already using the same 12x12 ceramic tile on the floor and walls. This tile is recommended for floor or walls. I attached 1/4" Hardibacker Cement Board to the ceiling in prep for the tiling.

1.) Is the 1/4" Hardibacker Cement Board OK for this application? I used it before for tiling, but with smaller tiles and it worked good.
2.) Can the Hardibacker Board support the weight of 12x12 ceramic tile?
3.) What are some key techniques for tiling a ceiling?
4.) Do you do a couple tiles (4?) at a time and then put a piece of plywood up and wedge a 2x4, 2x2 up and let dry? Fyi.. before when I tiled a ceiling, I tiled the backerboard on the ground leaving a few off so I could attach it and then lifted the whole backerboard up with the tiles on it, but that was with smaller tiles. I don't think this can work in this application.
5.) Do you apply the thinset to the tile first then put on the ceiling?
6.) What type of thinset do you recommend for ceiling application?
7.) What type of trowel do you recommend (U or V shaped)? How big?
8.) How much thinset do you apply to the tile or backerboard?
9.) How do you grout the ceiling and get the grout to stay up and not make a big mess all over the place?
10.) What type of grout do you recommend?
11.) I am going to use the same 12x12 tile from the ceiling & walls on the floor. I plan to use 1/4" spacers on the floor. Is there a problem with using 1/4" spacers for the wall and ceiling also? That way all the grout joints line up.
12.) The place where the ceiling tile meets up with the wall tiles, do I grout that joint? Or do I just use caulk?
13.) What type of spacer do I use at this joint if I am using 1/4" everywhere else? I would prefer not to caulk a 1/4" gap.
14.) On the floor tile, do I grout between the tub base and the floor tile or do I just run the tile up to the base of the tub about 1/8" away and then caulk it?
15.) The wall trim tile that I am going to use at the base of the wall, do I put a spacer between the floor tile and the bottom of the wall trim tile? Do I stay consistant with the 1/4" spacer?
16.) Do I grout or caulk between the floor tile and the wall trim tile?
17.) Should I seal the grout on the ceiling, walls and floor? What do you recommend?
18.) Do you typically continue the floor tile under the vanity?
19.) When tiling up to door to the bathroom, do you run the tile under the door casing or do you run it up to the edge of it?

Thanks for your help!