Your Personal Operating System

You have decided to write an operating system for your new, personal cell phone.  Your friends have decided that designing a cell phone operating system sounds like fun.  You are gathered together to discuss the issues, before you go off to write your own OS.
As a small group:
Research the following questions, and together write a brief synopsis of your answers.  You may subdivide your work if you wish, but all members are responsible for understanding the information provided by the group.
1	What hardware is available for a cell phone, and what are the advantages and disadvantages of each platform?
2	What is the difference between open and proprietary code?  What are the advantages and disadvantages of each?
3	What are the advantages and disadvantages of each interface: GUI, menu driven, command line driven?
4	What different ways can you handle processor/resource sharing, in a cell phone with only one CPU?
Write up your information is a readable (and not outline) form.  The nominal audience is anyone evaluating possible operating systems for a phone; however, be sure to show your group understanding of hardware, open versus proprietary code, different types of user interfaces, and processor/resource sharing.
	As an individual:
Using the information thoughtfully provided by your group, decide what approach will you use for each question, 1 through 4.  Explain why you made each choice.  Be sure to show your individual understanding of hardware, open versus proprietary code, different types of user interfaces, and processor/resource sharing.

Some of the following web pages might provide useful information:
https://www.uswitch.com/mobiles/guides/mobile-operating-systems/
There are a few main mobile device operating systems that the majority of smartphones run on,
 including Apple iOS, Google Android, and Microsoft's Windows Phone OS.

https://www.gearbest.com/blog/how-to/9-types-of-phone-operating-systems-2870
Android is open source (Google)
iOS proprietary; Unix-like
In iOS, there are four abstraction layers: the Core OS, Core Services, Media, and Cocoa Touch layers. The System operation occupies about 512MB of storage space. 

Based on Android:
colorOS
FlymeOS
OxygenOS
HydrogenOS
EmotionUI
MIUI

https://en.wikipedia.org/wiki/Comparison_of_mobile_operating_systems

https://www.makeuseof.com/tag/linux-smartphone-operating-systems/
Ubuntu touch
PostmarketOS
Sailfish OS (not open source)
Mobian
PureOS
Plasma Mobile
So why might you want a Linux desktop environment installed on your Android phone or tablet?