All these ideas are possible, it will just take a bit of organising in the dialog box to stop it getting too messy.
#1a Yeah, why not. It will be quite a few options with sorting first by top->bottom, bottom->top, left->right, right->left, plus the second sort in two directions; 8 possibilities, I think.
#1a I’m not sure what you’d call #1b with the numbers snaking up and down, but it could be done.
#2 Yes, just needs yet another text field.
Yes, it’s possible to take the component definition name and add a number after it.