In my opinion your nap time is way too late in the day. Try paying him down, or doing very quiet activities after lunch, like reading or watching a quiet video. Hopefully he'll transition to earlier naps and they will have much less influence over his bedtime routine.
No to the roaming or shutting them in their room. They are too young to be subjected to that. Once the kids are asleep in their beds they should be able to stay asleep most nights. Staying in their room and helping them drop off on those problem nights in the parents job.
The bedtime routine should be one of relaxing activities, a nice warm bath with some play, a snack, teeth brushing, all kinds of activities that are focused on calming the child to prepare for sleep.
Take note of what child care teachers do for kids having a hard time falling asleep. We would sit by their cots, pat them on the back gently, play soft music like ocean waves or a gentle rain storm, have the room at least semi dark, use a quiet voice when telling the to lay back down, etc....