How to appropriately emphasize the importance of consulting more to a student?
I have a completely different background, I'm in the lab very often and so are my students. Still they can become quite independent and it can be hard to keep an eye on what they're doing exactly. 

Suggesting to communicate more and persuading them to ask more questions is (in my opinion) the wrong way to approach your problem. You cannot expect a bachelor level student to learn - all by himself - both running a project and the science that goes with the project. Maybe that could work for the top 1% of students.

I'd start having weekly meetings, and then it's your job to ask them questions, teach them stuff and keep them on track. Suggesting someone to ask questions doesn't really work, so you should really ask questions yourself that force them to communicate about the project. 

Really sitting down and discussing the project will lower the barriers on both sides. Your suggestions won't sound like orders, and there will be no e-mail record of their silly questions. Start slow before you start having any real expectations. 

At the moment I'd be surprised if they even started with the project.