How do I explain Mrs. Elton's character in Jane Austen's Emma in terms of irony that amuses rather than disgusts?

The reason Mrs. Elton amuses rather than disgusts or
irritates, for that matter, is precisely because of Jane Austen's ironical approach to
drawing her character in Emma. This is well illustrated in Chapter
32 where we first get a good look at Mrs Elton. Austen writes Mrs. Elton's dialogue with
great gusto--words fly at a rapid pace through long phrases; Mrs. Elton will not suffer
to be read in a slow manner as she fills in extraneous details and flits from one
subject to another, all with the purest (misguided) sense of charm and appeal
imaginable, never entertaining the wild thought that only she could possibly be
interested in her brother and sister's modes of
transport:

My
brother and sister have promised us a visit in the spring, or summer at farthest ... and
that will be our time for exploring. While they are with us, we shall explore a great
deal, I dare say. They will have their barouche-landau, of course, which holds four
perfectly; and therefore, without saying any thing of our carriage, we should be able to
explore the different beauties extremely well. They would hardly come in their chaise, I
think, at that season of the year. Indeed, when the time draws on, I shall decidedly
recommend their bringing the
barouche-landau;

Another good
example of how irony keeps Mrs.Elton from disgusting us is her scene with Mr. Knightly
in Chapter 42 in which she boarders on offending the reader but is quickly brought back
from the precipice of disgust by Austen's mastery of craftsmanship and skill; by witty
irony; and by Austen's exquisitely precise characterization. Knightly has just proposed
the famous strawberry picking excursion and Mrs. Elton has just informed him that it is
she who will invite the guest for the excursion to his home--a suggestion that rightly
does not sit well with Knightly. Mrs. Elton's pushy approach is interrupted with
Austen's ironical tone first by Mrs. Elton's mortification at the thought that Knightly
would allow any other woman to orchestrate his guest list ("Mrs. Weston, I suppose,"
interrupted Mrs. Elton, rather mortified."). She is saved a second time from disgusting
by Austen's next ironical rescue in which Mrs. Elton acquiesces to Knightly, then
resumes her silliness by giving him commands on minutia to orchestrate how the day will
go:

… but as
you like. It is to be a morning scheme, you know, Knightley; quite a simple thing. I
shall wear a large bonnet, and bring one of my little baskets hanging on my arm. Here,
-- probably this basket with pink ribbon. Nothing can be more simple, you see. And Jane
will have such another. There is to be no form or parade -- a sort of gipsy party. We
are to walk about your gardens, and gather the strawberries ourselves, and sit under
trees; ....

So, Austen saves
Mrs.Elton from being disgusting by (1) employing an ironical tone; (2) characterizing
Mrs. Elton as innocently vain instead of arrogantly vain; (3) making her a very silly
person who has a doubtable grasp on logical order of thought; (4) giving her a quick and
lively personality, albeit a silly one; and by (5) giving her some redeeming qualities,
like her devotion to her husband and to Jane Fairfax: “I shall bring Jane with me --
Jane and her aunt.”