Most Design & Drill products are aimed at preschoolers — listings commonly show "Suggested Age: 3 Years and Up."
Piece counts vary widely across the line, ranging from as few as 1 piece up to about 125 pieces depending on the set.
Product descriptions list the toys as made from plastic.
Yes — listings state the drill and bolts are compatible across the Design & Drill range and that the drill "works with bolts from any Design & Drill set."
Typical contents include a kid-friendly power drill or screwdriver, colorful bolts (commonly 6–60), nails or a hammer in some sets, basic hand tools, play pieces or figures, and sometimes a workbench or playset with storage and activity guides. Battery requirements are listed for many sets.
Yes — some sets use packaging that unfolds or pops out into a reusable playset or scene, and product text explicitly notes the box can be turned into an imagination-boosting playset.