Membership System (Advice and Process needed)

Hello so i wanna create a multi-tenancy system with the following features;

membership system (with a unique id(e.g: CHM/GT/000 for each member)where *CHM* is initials of the church *GT* is the branch and *000* is the number of the member. Also member should be able to belong to a group or more groups example "Employee" while as maybe can also belong to finance...

forum module ```forum should be such that a guest can create a discussion and so can a member but all post must be reviewed by the forum master before accepted, also forum users should be able to post for admin or forum masters eyes only.

blog module ```(Can upload video and audio) under various categories such as (sermons, teachings, events,) includes subcategories too)```

mail module ```(Manages mailes of all users with emails with the church.
finance module(Transactions, Income; Tithes, Donations, Offerings, Expense etc```

event/program module ```(list all weekly, monthly and annual events from a predefined calendar. featuring cureent or next event.```

so i want the website to be as lite and fast as possible. Now my hustle is do i code it from scratch or what admin panel is well recommended for such a system. the application is a church management system.

Any advice is much appreciated