First is the wood floor over plywood or just directly to studs. Is it the standard 3/4" thick? If it's over plywood all you have to do is morter down 1/2" concrete board, screw it down and fill in joints and screw holes with morter. Then you can thin set your tile. Good luck.
In my opinion, no. For more reasons I can count. The added height will create an awkward transition and tripping hazard to any adjoining flooring. You might also have to cut down all doors to account for the additional height. Did that thought cross your mind?
My vote is to do it right. Remove old flooring, inspect sub floor and make any necessary repairs, lay new tile, grout and seal. Then enjoy your new floors for decades to come.
Hi. It is never recommended to lay flooring over top an existing floor.
Not directly, you should do a bit of research to determine how much work you are willing to put in to this project to see if it's a feasible option for you. For example, you must have a truly solid base to screw the concrete board to. You would have to fasten the old hardwood to the floor joists, and then be sure you don't end up with low spots, which would require working with a self leveling compound. Another consideration is the transition to adjoining rooms or hallways. Hardwood + backer board + thinset + tile = quite a bit of a rise from on floor to another!
NO! You need to make sure the floor is level. Then install cement board over the wood floor. Then you can install the porcelain tile.
How about vinyl? Is it compatible with wood flooring? Thing is, I am not fond of the existing wood floors. They are in poor condition, with too skinny of a plank and the wrong color.