Trying to make a wemo like project - need help/suggestions

Hi all, I just got into this espruino yesterday and I am so excited and loving it. this is amazing. It completely open up my possibility on building cool stuffs that I never thought about. Thanks for building such a great community. Anyway, back to my project. so I am planning to build something like the Belkin Wemo. an advanced ver of the wemo.

My Goal:
I want to automate my fish tank on refilling water whenever the water level drops to certain level. I m using one water level sensor, one temperature sensor and two switch to turn on/off the water pump and a heater. and of course the esp8266 board itself.

Main features:

1. sends the water level/temperture to my webserver every 30min/hour
   
2. monitor the realtime water level and temperature from my browser(phone or app).
   
3. be able to turn on/off the water pump from my browser (send a request to my esp8266 from my browser)
   
4. when connected to the espruino from broswer, the temperature/water level value update itself on webpage as soon as the actual value changes. Not via refreshing the page manually or doing a pull to the esp8266. I would like the esp8266 push to the browser whenever the value is changed.
   
   

My Roadblocks - I got stuck at 3 main issues. I am not sure what to do here. Hope you have some suggestion for me.

1. since I don't have a static IP with my home internet, how do I get the correct ip address whenever my ip is changed? because I need to send the new ip address to my server and store it to db so I can send request to back the esp8266 to turn on/off the water pump and monitor the realtime water level/temperature value.

2. how do I get the realtime temp/water level update by itself without doing a pull from browser? I am guessing I need to use socket right? if so, please provide some reference on this. if not, what would you do to achieve this goal?

3. How do I update the wifi login info without hard code it to the code using the IDE? I want to be able to update the wifi login info using my phone whenever the wifi password is change. I want to make this board as portable as possible.

Thanks for reading and Hope you have some tips for me to solve my two issue.
Thank you.