Wow! That's so generous of you!
This enclosure is really super stable! It has that good industrial feel, where everything is rigid, quiet and professional.
Q1: I've placed electronics (you can see which power supply and voltage regulators I used in the BOM and electrical scheme) in the back bottom of printer enclosure. You will find it in the build photo gallery.
Q2: Learned from aerodynamics - you need at least 2x larger input area than exhaust area. That is provided with 5 holes with "vent covers" on the bottom. They are placed in the edges + 1 in the middle. The one in the middle is usually closed, to prevent airflow around the bed.