I have a small (about 12" high x 10 " wide by 8-9 " deep) 3-drawer unit I keep all my sharp items in(rotary cutters, scissors, all needles and pins). When my grandchildren came and slept in the sewing room I simply carried this unit to my bedroom so there was no worry about them getting into those things.
I also use a telescoping magnet wand to pick up all pins, etc that may be on the floor.

Lock them up In a safe and put the key away in a safe, high place.

Sandy

It depends on when you want to sew and how much stuff you have. I would divide the room with 3 shelf units or cube cubbies back to back. some for you and some for kids toys with a baby gate or half door at the end of shelves to keep kids out of your stuff. Scissors and rotary cutters on peg boards above your work station. I have my fabric folded and stored in elfa drawers with plastic liners (the shorter ones) with a top on it. two 3 rung drawers and one 1 rung drawer holds larger hunks of fabric and thread and fusible web in top drawer. The other has three 2 rung drawers and one 1 rung drawer. The larger drawers hold my fat quarters and other is currently empty but could hold rulers/templates etc. I also have a couple of tall white cabinets with doors. Add a cheap hook latch up high to keep dangerous things hidden a another step away from the children. If you don't really intend to sew when the kids are awake, I would choose the basement if you can keep them away. It won't need to be as clean or organized and you can leave your projects out for those short 20 minute naptime getaways.

One of the close up sewing centers would probably work really well for you. You can get a magnet and clean up the sewing area after you're finished and then close up the center with everything in it. The down side is most of them aren't are a bit pricey. Koala is the big fancy one but there are cheaper alternatives. Horn is one brand and I know there are others.