Welcome to the forum, Omar.
You have the general idea on tiling over what you have, but there are some particulars that need to be addressed.
Can you get the specifications on the floor joists and plug them into the Deflecto in the blue bar at the top of the page? Let us know what you come up with.
Generally speaking, you'll need a layer of plywood over the planks you have there. But tell us the specs on the planks (and the joists) so we can tell you what plywood to get.
As for the toilet, what kind of plumbing is it? Cast iron, ABS, PVC?