So I want to stack these 2 shields with 1 Arduino Leonardo, Leonardo is powered with 12V adapter and connected to Windows PC via USB.
Any suggestions, I'm new to Arduino and would like to learn my mistakes. (Ethernet shield's pins is not bend it looks like that because of my camera 
)
Powering an Arduino thruogh Vin or the power jack with 12V is ill advised. Connect your 12V to a 5V DC-DC converter (buck converter) and connect the 5V to the 5V pin.
List the pins used by each shield and for what the pin are used to look for conflicts.
first you have to plug in the Ethernet shield, because the SPI lines for the Ethernet shield come from the 6pin ISP header.
I'll get a converter tomorrow asap, I'll use my USB shield to power my mouse while researching about this topic I saw some people that suggested using 12V power jack because high consuption by mouse.
About the other question, both shields bottom part looks same here is the photo. (Thanks for fast response <3 )
There is SPI lines from USB Host Shield too afaik (I might be wrong about this but both of the shields bottom part look identical).
If powering the Leonardo with 12 volt to Vin because the mouse needs current is a direct disaster. If You're lucky the controller board will shut down due to overheat. If unlucky, there might be smoke coming.
I already switched to only micro-USB power and I'll get 5V converter for adapter, still open for ideas about how to daisy chain shields.
Answered by @groundFungus in post #2:
List the pins used by each shield and for what the pin are used to look for conflicts.
Basically make sure that the shields don't have pins in common besides 5V, Vin and GND. Unfortunately the poor documentation of most shields can make this a hit or miss proposition.
Pins like SPI pins (SCK, MOS, MISO) and I2C pins (SDA, SCL) can be shared by SPI or I2C devices. Chip select pins, RX, TX pins, for instance, cannot. There must be a chip select for each SPI device. Serial ports can't, grnerally, be shared. So you need to know what each pin is used for in order to avoid pin usage conflicts.
Sorry for late reply, I changed my approach to this and decided to communicate using Bluetooth, and ordered a HC-05. I currently have a Leonardo, ontop of that a USB Host Shield and I want to connect my HC-05 to 9,10,11 and 5V, GND ports. Does this approach works or can you spot any problems? (I got the 5V adapter thanks for early warning)
Probably not with good reason. Leonardo has hardware serial on pins 0 1. It is called Serial1.
Also, you should have a 1k/2k divider on Arduino Tx.
I don't know if this has been said or not:
Cover the top of the USB port on the USB host shield with tape(Ideally electrical tape.....) so it does NOT touch the bottom of the. Ethernet shield.
So there is weird things going on, I configured HC-05 in AT mode and tried to connect but Windows gives this error? Any tips to solve I'll gladly follow them, also Red LED is flashing fast but no sign Blue LED. HC-05 connected to 10,11 on arduino leonardo with usb shield ontop.
AT mode is for setting up the HC05 not for communicating. The Arduino nor Arduino code have little to do with connecting the HC05 to the PC.
First you need to pair the HC05 to the PC. The HC05 must be in slave mode to pair with the PC.
Once paired, conncect the HC05 to an app. For testing I use the Bluetooth terminal app by Kai Morich (available in the play store).
So, to pair the HC05 must be in communication mode and configured as a slave.
Once paired, most HC05 units will use a default baud rate of 9600 talk with the Arduino.
I already set it into slave mode but what should I do to get it into pairing mode, when first I connected blue light was flashing too now it’s not is that normal? And I tried to check via my phone Bluetooth and can’t managed to see HC-05, maybe it’s because I use IOS device?
I have never seen a HC05 with 2 LEDs. Are you sure that you have an HC05? Can you post photos, front and back?
Where did you get it? Can you post a data sheet or any other documentation?
That, indeed, looks like a HC05.
I apologize for the wasted time. Somehow I misses seeing that. As far as I know, you cannot connect a classic Bluetooth device (HC05) to IOS. You need a BLE Bluetooth device, like HM-10.
I want to connect HC-05 to my pc not IOS, I just tried to check it. I just can’t pair it with my pc I can send AT commands and chip executes all commands fine.
