I just tiled 2 bathroome and a bed room, should I use grout sealant or not. Are they all the same, I see they sell so many different brands.

Hiyas. I have a house built about 1930ish or so. It's a Brick ranch with a "finished" cement block basement. I say "finished because it has nasty, way out of date yellow and green tiles for the floor that are half peeled up and lovely paneling strips that are pulling off the walls. It is in my mind to make this basement a bit nicer as it it is huge and would be a great space for rec room, kids playroom etc. I have a question about the water though. It does get seepage during wet weather though not usually noticible except for multiple days of rain or the like. There is a gutter built into the cement floor that drains water around the edges to the lowest corner and into a drain. Firstly, would it be feasible to have the basement waterproofed and would it be safe? i.e. would the water then just sit against the wall and eat away at the foundation for the next X amount of years. Secondly is there a decent, affordable moisture resistant type of wallboard that would work well for basements. I know there is drywall made that is moisture resistant but I'm just curious about any other products out there. As far as the floor is concerned, the tiles that are cracking and peeling up are no problem but the rest seem to be on to stay. The amount of work needed to get them off make me wonder if t here is a filler/coating made for this type of work that would just fill in and level the existing gap's and coat the remaining tiles and then I could just do whatever I decide over that for a "new" floor. Your thoughts and ideas are greatly appreciated!