1 - https://maxivz.gumroad.com/l/ynJmIV
It have “Smart Delete” function. In case of Vertices - it will delete them. In case of face - delete them and in case of edges - dissolve them.
Ofcourse you will need to assign some hotkeys and so on.
2 - When you create new object check the undo panel* There would be a setting called - Align.
By default it set to World, if you change in to 3D Cursor you object will rotate and match you 3D cursor rotation.
*undo panel - its a panel which you can see on the bottom left corner of 3d viewport after you create object, use some tool and so on.
3 - First of all you need to enable Face mask mode. Its a 2 buttons with a face and vertices icons on top left menu of vewport. Right to the dropdown menu where would be written - Vertex paint mode.
Only after you enable you Face or Vertex mask, the Selection tool will appear in toolshelf.
Also: you can select any face/vertices in Edit mode and when switch to Vertex Paint and enable face/vertex mask button.
11 - Only with addons. https://github.com/Shulito/fit_lattice
There’s also some paid one like: https://blendermarket.com/products/fit-lattice
18 - Nope. Blender doesnt have selection sets feature. https://www.blendermarket.com/products/zen-sets
Or if you under Blender 3.x you can use free addon with selection sets feature: Forgotten tools
20 - Im not sure but if “poly island” = loose parts, i.e. if you have 2 objects joined together (but meshes and NOT connected, i.e its 1 object with 2 meshes which doesnt share any single vertices) and you want to select all faces on one of them, then the answer is - not really.
Select > Select Linked will select obly loose part (and other types) but assign this specifically to double click? I guess its can be achieved with PieMenuEditor addon (Im really highly recommend this one) but i cant guaranty that. https://blendermarket.com/products/pie-menu-editor
23 - Im not really understand you question, but anyway: limit method are doesnt do anything with vertex normals at all, its just a way to tell the modifier which edges should be beveled.
Just a personal recomendation: if you doesnt want to use vanilla blender hotkeys and want to customize blender a bit - PieMenuEditor addon can really be you best friend.
Im personally heavily dislike blender vanilla hotkeys and generally UI related stuff (i was came from 3ds max) so i customize it pretty heavily.
PieMenuEditor are not only provides you pie menues. It capable of creating regular menues (like the one on the RMB), creating some macros. You can put one pie inside another pie. And you also able to run different commands with 1 single hotkey depends on context.
Like one menu when you in object mode, another one when you in Edit mode, and even if you want 3 different pie menues for Vertex, Edges and Face mode - you can do it easilly and all of that would be called with one single hotkey.