3 strange issues that I desperately need help with!!!

So to start off, I have NOT had any of these issues until this weekend. The only recent additions to my game were a few rolling stock items from the RWA library. I have done/used all of the things I'm about to describe before WITHOUT issue until this weekend. I don't know if these issues are connected or not, but here goes nothing...
When resuming a previous free roam scenario that I created for Soldier Summit, I went to use the D&RGW Heritage SD70ACe. Upon entering the cab, with expert controls and F4 HUD up, I noticed that the train and dynamic brake function keys were not working, but the locomotive brake was. All brakes functioned normally when using the HUD controls or cab controls. All other key functions operated as normal.
So with those issues, I decided to edit the scenario and remove that particular unit to see if the issue was just with that locomotive. Upon the scenario editor screen loading, this is what came up. Almost pitch black screen and it was EXTREMELY laggy like it wanted to freeze up. But when leaving the editor back into the actual scenario, the screen returns to normal.
My third issue is with the Sherman Hill SD70M and ES44AC (have not checked the SW10 or SD40-2). These I cant operate the brakes at all via keyboard control. When using the HUD or cab controls, I can operate the brakes. But, the locomotive brake will not go below 20% at all. The train and dynamic brakes will operate, but will not operate with accuracy. If I want to set either to say, 30%, it may either go to 33% or 28%.
I'm EXTREMELY confused as to what is happening and I'm VERY computer ILLITERATE. Any help will be appreciated GREATLY. Please let me know if I can provide any more information that might be useful!!!

PS; I am currently checking if any other routes have the editor issue and if any other locomotives have the brake issues.
When resuming a previous free roam scenario that I created for Soldier Summit, I went to use the D&RGW Heritage SD70ACe. Upon entering the cab, with expert controls and F4 HUD up, I noticed that the train and dynamic brake function keys were not working, but the locomotive brake was. All brakes functioned normally when using the HUD controls or cab controls. All other key functions operated as normal.
So with those issues, I decided to edit the scenario and remove that particular unit to see if the issue was just with that locomotive. Upon the scenario editor screen loading, this is what came up. Almost pitch black screen and it was EXTREMELY laggy like it wanted to freeze up. But when leaving the editor back into the actual scenario, the screen returns to normal.
My third issue is with the Sherman Hill SD70M and ES44AC (have not checked the SW10 or SD40-2). These I cant operate the brakes at all via keyboard control. When using the HUD or cab controls, I can operate the brakes. But, the locomotive brake will not go below 20% at all. The train and dynamic brakes will operate, but will not operate with accuracy. If I want to set either to say, 30%, it may either go to 33% or 28%.
I'm EXTREMELY confused as to what is happening and I'm VERY computer ILLITERATE. Any help will be appreciated GREATLY. Please let me know if I can provide any more information that might be useful!!!

PS; I am currently checking if any other routes have the editor issue and if any other locomotives have the brake issues.