Hai
How to get fixed ip for ESP12E And ESP8266
How to control ESP8266 Android app And Amazon echo And Google Home Please Tell
Get fixed IP ? Erm, You either set a fixed ip in your code, or you let it get its address via dhcp from your wifi network. Look at the examples that are provided with the ESP8266 Arduino interface. Communicating with Alexa or Home is not a simple question to answer, there are plenty of examples out there of people that have done it, but they tend to be quite complex
4 relays, 4 io lines, set those lines to outputs then digital write them high or low, this is “my first Arduino program” stuff, you really really need to go read some tutorials
Try kakopappa github for multi device esp8266 library