>     Not all the way there, but I don't know what to do about the format
>     complaints.

The suspect that problem is that your definition of `ebdb-add-to-list`
duplicates its argument, so

    (ebdb-add-to-list X (format FOO BAR))

becomes

    (when (format FOO BAR) (push (format FOO BAR) X))

Since `format` always returns a string, the `when` can be optimized away
so the above becomes:

    (progn (format FOO BAR) (push (format FOO BAR) X))

Beside the useless call to `format` there are other minor problems with
this definition of `ebdb-add-to-list`, such as the fact that its
arguments are not evaluated in the expected order (left to right), and
the fact that the second argument gets evaluated twice, so:

    (ebdb-add-to-list (progn (message "hello") 'x)
                      (progn (message "world") 3))

ends up adding 3 to x and emitting

    world
    world
    hello

instead of

    hello
    world

But the more serious problem is that `ebdb-add-to-list` is defined as
a function yet it can't work as a function because its first argument is
expected to be a "place" not a value.
So you have to define it as a macro rather than a (define-inline) function.

Also, personally I'd recommend you rename the to use a word like "push"
(and to switch its args) rather than `add-to-list`, so the reader can
guess that it takes an place, like `(cl-)push(new)`, rather than
a symbol, like `add-to-list`.


        Stefan