sign up visitor profile

Hi,

In my Twenty Fifteen menu bar, I would like to add in a tab called “sign up” in my main page. What I want is that when a site visitor visit my multisite (main page) and click on “sign up” tab, after he/she register to sign up, the multisite will automatic assign a new site to this registered visitor to serve as their profile account. In this account they will have all their booking record, history of transaction, or they can also be able tocontrol their booking appointment by either cancel their appointment or reschedule their appointment. Basically, the main purpose of this register account is to keep a record or history of their activities. For example, account holder A, go to different site of my user site (salon owner) and make several appointment, give out several review on several user site, and also buy some gift cards. Then a few months later, this account holder will go back and still see their history of activities.

(For example, if I visit one of the website and I want to sign up for an account, after I signed up I get an account just like a regular website where it have a menu bar with several tab and I also be able to insert my image with my name underneath.

So my question:

1. How to install a “sign up” plugin into my Twenty Fifteen theme menu bar and what plugin that I could use for the multisite to assign a new site for my visitor after they signed up.

2. Since registered visitor (or account holder) can not get access to dashboard, is there a way that this registered visitor just click on the header image location to upload their image directly from their desktop? and is there a way that multisite automatic greet the registered visitor with a text that say “welcome to your profile, Adam Smith” (for example)?

3. In the registered visitor account will have a menu bar with several tab such as appointment, profile, bookmarks, reviews, gift cards…etc. Is there a plugin that keep track of of record of visitor activities under each tab?

4. Is there a plugin that allow register visitor account holder to change/reschedule their booking appointment?

Sorry, for this long descriptions and many questions. I hope is clear enough for you to help me. As always, I really appreciated for your great supports.

chad