If the drain is adequate size, 3inch, then you could.
You don't have to have one, it just makes it a little easier. As long as the drain is flush with the floor, you can drill into the concrete and us anchors to hold the toilet down. The down side is that they tend to corrode over time and become stuck in the concrete. If you ever have to remove the toilet, they can break and that makes putting the toilet back harder. You can just bolt a mounting ring to the floor and use regular toilet bolts to hold the toilet. These can be easily replaced if needed.
seal to stop water from runing into tank located between tank and bowk
cc means a close coupled ie a toilet pan and cistern which are attached to each other by bolts and a washer cc can also mean copper to copper... ie: sweated / soldered connection.
You have to use toilet more
Replace to inlet washer this normally happens when the washer develops a hole
sounds like you are going to need to install a sump for the sink to drain into and then you put a sump pump at the bottom and connect it into the houses main line.
No.
Toilet flappers is the washer underneath the flushing mechanism. Normally black or orange in colour.
Without knowing the layout or type of drain pipe and location, it is impossible to give a good answer. Drill a hole in the floor and run the drain with PVC. Drains should fall 1/8 to 1/4 of an inch for every foot of distance. Horizontal distance. There may be a drain line that is closer to the first floor location that you can tap into. Washer drain does not need a vent, it gets it's venting around the washer hose.
you need a hammer arrester. They sell a nifty hammer arrester that will fit on the pipe supplying the toilet without having to use a torch. fairly cheap ($12) and easy to install. A loose washer in the toilet shut off valve can cause this problem.
When you pull the handle a washer is lifted and the water goes down into the toilet and at the same time the cistern fills up once the washer is back in place from the flushing mechanism
I would use a pressure washer.