That's a pretty big drill bit, -it drills a hole just a tad larger than 3 3/8 inch wide.
A 3/16 drill bit.
Removing the Key Switch requires a special torx bit screwdriver with a hole in it, or you can use a basic torx bit and use a drill with a small bit to drill out the center part of the screw with the stub in it that wont allow a normal torx bit to go into.
Use a standard HSS drill bit, but slow down rotation to about 500 rpm.
Depends which screws you are going to use. I usually use the #6 screws that come with blinds. They need no pre-drilling.
Search for "stud extractor". Looks like a drill bit but the cutters are left hand thread, designed to be used with the drill in reverse. The lid of the box or the extractor should be marked to indicate a) the screw size they are designed to extract b) the drill bit size you use to drill a hole for the extractor. Before you start apply some penetrating oil. 1) Select the correct extractor for the bolt size. 2) Use a punch to make a dimple in the centre of the snapped shaft. 3) Drill a pilot hole a few mm deep with a drill. 4) Put the drill in reverse with the extractor in it. 5) Put the extractor in the hole and go for it. 6) If that doesn't work buy "freeze and release" spray and use as instructed then repeat 5).
The easiest and most effective screw to concrete method is with the use of TAPCONS. A box of these screws comes with a supplied masonry drill bit of the appropriate size to use in predrilling a hole in the concrete. The hex or Phillips head screw is then run through the item being fastened and into the concrete until the desired depth is achieved. Look for the 3/16"-1/4" diameter screws of various lengths which are blue in color.
if you can reach it, drill the center of the screw shaftout, then use an easy out.
Low angle makes it three drill lock system.
The bit is called a countersink bit, but be sure if it's to be used in stainless that it is made from high speed steel (for metalwork) or carbide tipped and turned at a low speed. Use a good grade of cutting oil as a lubricant.
Very slowly with a Carbide drill bit or Diamond core bit, both will work, but the diamond core bit works much better, make sure the bit has a constant flow of coolant or be submerged in the coolant. (go very slowly, do not apply much pressure, let the bit do the cutting) The best way is to use a drill press but a hand drill will work.
A 40mm masonite drill bit could work using the right drill. But consider using a coring machine instead because its concrete.
Drilling ceramic tile can be accomplished with a carbide tipped drill bit such as one for masonry or concrete but a better choice is a bit designed to drill glass which is much harder Most home improvement stores carry such bits and they are only a bit more than regular bit sets. A glass bit looks like a spade on the end of a shank while the masonry bit looks like a traditional twist drill.