Dev Mode: Edit or View?

First time poster, long time fan of Figma :) Since the changes in March, I’ve been struggling to get developers to understand how to get access to the file. It’s been chaotic. 
 

TL;DR - if I add developers in Dev Mode, with VIEW access, shouldn’t they be able to inspect designs? Do all the Dev Mode things? I don’t want them to edit ANYTHING (anymore). 

There are several places this process may be falling apart, so I’ll explain: 

1. I’m in an enterprise, and a different department manages permissions. Figma is new here, and we’re working out the kinks in the other department. I was told to invite the developers to the Figma file, so I used the Share button and added their emails with View access. 
2. I’m working with about 20 vendor developers, some onshore and some off. I don’t think any of them actually read the instructions in any emails, including mine with screenshots. 
3. The delivery file I have invited them to, I added them in dev mode with view access.
4. The ones that managed to complete the process by opening the email and clicking through said they couldn’t access the file.
5. I switched their permissions to Edit, and that seemed to work.
6. Still adding more developers, but some of the ones already in the file have accidentally deleted, moved, or modified content. I’m resetting things daily. When I switched it back to View because they were deleting and moving things, they emailed me saying they couldn’t access the file again. 
7. It’s still in flux, delivery deadlines are tight, so 3 designers are editing constantly, so I can’t monitor to keep everything locked down all the time, or trust that the designers will remember to lock (they’re still new to the software). 

Some possible reasons

• Dev-side Problems: Devs new to the software that may not speak English aren’t understanding the instructions or the multi-step process - ask me for invite, then open email, then clik on a link then click on a button to ask for access then wait for it to be approved by the other department. Any of these steps could be the problem. This is not Figma’s fault. 
• Dev-side Timing Problems: Also not Figma’s fault lol - the developers were impatient and tried to access even though the switch to approve hadn’t been flipped in the other department. 
• Enterprise Settings. I’ve never admin-ed in this new structure. The current admins have never admined Figma. Anything about enterprise settings (we have very high security requirements), or the other department’s setting/choices could be the problem. I absolutely do not want to tell them what to fix unless I know exactly what the problem is and how to resolve.  

If View access should work for developers to use Dev Mode to access specs without moving and deleting things, are there any ways Enterpeise settings could be screwing this up?