Cake day galore

I stocked up on keys over the past months with the intent of doing a sizeable puzzle, but I never got around to designing the huge puzzle I wanted to do, and ConanOLion reminded me that it's my cake day... so instead, you get a handful of lazy puzzles and some trains (everything lvl 3)

Anyway, word of the day is cake, I hope you have some.

Please Stand By
Picross time
You know what it wants
Think like a computer
Enter the password

Have a day!

Notes:

• 38 giveaways in total
• All 6 trains have hidden giveaways
• Puzzle 4 is case ignorant, so maybe half of what you think is necessary, is unnecessary.