Names have been changed to preserve anonymity
A group of 25 people, A to Y, arrived at Z's door to celebrate the family reunion. They each had something to show off.
Z: I know you're all excited to get in, but remember we've got we want to say to the community. To make sure you're all ready, I need you to finish this off. Then you can say what you want. (pointing to a group of people) You lot will always be important at the start, but (pointing to N and two others) you three will be needed at the end of everything. Now let's get started!
What was the message to the community?
A lot of people have complained about not being able to distinguish between different arrows. If you click on the picture, you can see the image in high enough resolution to solve the puzzle.
Revisions 7 and 12 - Fixed sudoku - will not have affected your ability to solve the puzzle. The problem that was fixed did not affect any existing solution, nor should it have affected your solve path (unless you work strangely). However, it may be worth redownloading the image if you have a copy on your computer.
What are the different types of arrows?
The arrows do not form part of a cipher.
Note what comes first and last in the accompanying text - it's not pure flavour-text!
Specifically, at the start there a group of letters, (something in the middle), and 3 letters (N and 2 others) at the end.
Clicking on the image or editing this post will reveal what you have missed (and no for the people who are wondering whether anything is hidden in revision history)
Each 5x5 box can be done separately.
Apart from the problem statement and the image, where else could the next step be? (It is in a place approved by the Puzzling community)
The (something in the middle) of Hint #4 is represented by the arrows in each box.
Minor changes to the sub-puzzles (Only look at this when you've found them!):
LITS - https://i.stack.imgur.com/0OH3y.png
Moon-or-Sun - https://i.stack.imgur.com/rMfYK.png
Hotaru Beam - https://i.stack.imgur.com/uqDyf.png
Usowan - https://i.stack.imgur.com/kP5NX.png
Nurimeizu - https://i.stack.imgur.com/p83VE.png
Atypical rules of the sub-puzzles (Only look at this when you've found them!):
Moon-or-Sun - no alternating moon-sun rooms condition
Corral - the loop goes along the squares like in this small grid - http://i.stack.imgur.com/jyXRi.png