Empty Hallways

 I recently filled up one of my graph paper notebooks. This inspired me to go back through the notebooks I used before that one to see if I had any cool old puzzles lying around that I had forgotten about. The following puzzles were probably drawn in late May 2022, except the rightmost puzzle here was re-clued today to avoid what might've been a nonuniqueness. I have suspected that I first came up with this puzzle idea as far back as 2016, making this the ultimate recycling of my ideas. These puzzles do use a slightly adapted ruleset, but I think it's better than the original rules.

Shade some cells to form walls, such that the unshaded cells form rectangular rooms. Then, connect the rooms by drawing hallways in the pre-marked light gray cells. A hallway is either a straight line or a turn which connects two rooms. All rooms must be connected through the hallways. The letter "h" has been used to represent chairs, which cannot be shaded. 

penpa link (no answer check)