Could you please check these sentences?

Thank you.

1) "It's a pity you didn't read that book," he said.
He regretted that I hadn't read that book. (Is it the only possible form?)
2) Try eating less.
Try to eat less. (Are both possible?)
3) He was seen stealing the watch.
He was seen to steal the watch (are both possible?)
4) He admitted/confessed (to: can "to" be omitted) stealing the money.
5) She ordered me to fill in the blanks.
She chose not to take the bus.

1. He thought I should have read that book.

2. Both OK

3. The first sentence is fine; the second is not.

4. Keep "to" in there.

5. OK