Help with research project: MP3 shield connection to Mini Pro

Hi all,
I've been collaborating with friends to try and build a birdsong broadcast system out of Arduino components for my PhD research. However, we're having trouble getting the MP3 shield to work. A list of components, a table of the connections, and the code are available here: GitHub - justinthomasmann/Arduino-Birdsong-Broadcast-System

Here's a summary of the progress we've made so far:

First, with the wiring the way we have it, the MP3 player doesn't seem to be getting power. We hooked up analog pin 0 from the Mini to +5V on the MP3 player, and doing a digitalWrite(A0,HIGH) causes the speakers to click... they are now getting power.

When we use the Adafruit VS1053 library, there are two ways to initiate the VS1053 interface... one is the 5 pin initialization using the SPI libarary. This is what worked with the Uno, but when we run it on the Mini Pro, the spiRead routine hangs up. The other way is to specify the 4 SPI pins using an 8 pin interface. When we use this, we don't use the SPI library, but we get back all zeros from the SPI interface, no matter what, even after writing to the SPI registers. I'm assuming SPI communication is not working correctly somehow, but I'm not sure how to debug.

We can't even get past the "begin()" call, so we have no way of actually playing an MP3.

I have limited time to get this system up and running, so any help or advice would be greatly appreciated!
Thank you,
Justin Mann

Circuit diagrams were helpful, of the mp3 player and your total system.

Driving the +5V pin of the player by a digital output won't work, the player requires a more powerful supply.

I see no reason why a sketch shouldn't work on a Mini, when it works on an Uno. You're doing something wrong.