This is a lot of stuff. Personally I feel adding even more fairy pieces will just be too much, people will be WAY too confused and will simply not play fairy pieces. Fairy piece variants already have the least play of all variants (besides, maybe, Arena of Legends, but even that has become less popular lately).
Also, these are not all the changes (you call it a "compendium" but really just use it as a way to introduce the pieces you want added).
What has also been suggested is to add a feature in the position editor that dictates which direction pawns move based on the board geometry, I feel this could greatly diversify and improve variants.

see the difference?
This is just a compendium of changes that have been suggested by anyone. So if anyone who works on chess.com ever decided to make changes there would be a long list of them-
ok it's not really a compendium yet because I only have a few other peoples pieces
but PLEASE IF YOU HAVE ANY Possible pieces or setting comment them here- this is not a list of good settings of pieces just possible setting or pieces
{New pieces}
(for all new pieces names are all suggestions)[and reasons for name are in brackets]
- archer(an Afli that skips two spaces diagonally)[because it shoots an arrow?]
- crossbowman (a Dubbaba that skips two spaces)[because an afli moves kind of like a bishop and in medical times the church (bishops included) outlawed crossbows. And because medival archers used these to defend castles (aka rooks)]
- Arbalest (archer and crossbowman combined) [cause an arbalest was a better type of crossbow]
- wazir rider - can make as many wazir moves as it wants but it can turn.
-Tunnels- stationery pieces that are kind of like a wall but you can move your piece onto it and it comes out on top of another tunnel.
{additions to peices}
- Grasshopper rider (you know what this would be)
- wildebeest rider (you know what this would be also)
-archer crossbowman and arbalest riders? (you know what this would be too)
- NO brakes topping {maby like a little X on top of the piece?} -makes is so that a piece with this (aka queen, bishop, knight rider, etc) could not stop and had to go the farthest it could, like until it hits a wall or captures.
{new settings}
- Possible making a player a "zombie" he still gets to chose which piece he moves but he has to play by his zombie's constraints like if the scenario creator decided that yellow was a checker yellow would if possible have to check. AND you could also make a player immune - you would just make for example the other players have a lot more points to start with.
- what I said in this post fractional and adjusted points
- A ability for the game designer to change the way pawns points (like he could make everyone's pawns go the same way