Inheritance in Sense & Sensibility

Elinor has £1000 (inherited from the Old Gentleman) which will bring in £50 per annum invested at 5% (see Chapter 1). Edward has his own £2000 which invested at 5% will bring in £100 per annum (Chapter 37), and Colonel Brandon says the living at Delaford will bring in £200 p.a., but is capable of improvement. That makes a total of £350 per annum income.

However,I think this passage form Chapter 50 indicates that Edward on marriage gets,as did his sister, Fanny, £10,000, from Mrs Ferrars:

What she would engage to do towards augmenting their income, was next to be considered; and here it plainly appeared, that though Edward was now her only son, he was by no means her eldest; for while Robert was inevitably endowed with a thousand pounds a year, not the smallest objection was made against Edward’s taking orders for the sake of two hundred and fifty at the utmost; nor was anything promised either for the present or in future, beyond the ten thousand pounds, which had been given with Fanny. 
Chapter 50

If I am correct and this means that Mrs Ferrars gives them £10,000 because that is what she gave Fanny when she married John Dashwood, then the income from that money when invested will provide them with an additional income of £500 per annum. Elinor’s income on marriage is very near that sum which she thought was perfection:

Chapter 17

Elinor laughed. “Two thousand a year! One is my wealth! I guessed how it would end.”

That makes a total of £850 per annum before improvements at Delaford.

On that income Sarah and Samuel Adams calculate that the Ferrars could employ the following:

Income £600-£750 per annum: A Gentleman and Lady with children may keep three females and two men. Viz- A Cook, House-maid and another female servant;a footman and a groom who may assist in the garden and a gardener occasionally. 
The Complete Servant(1825), page 16

If however if I amwrong in interpreting that passage,and the Ferrars didn’t have that extra £500 per annum, then on £350 per annum they could still, according to Sarah and Samuel Adams, expect to employ the following staff:

Income per annum £300. A Gentleman and Lady with one ,two or three children. Two maid servants. 
As above page 16

So, no need for Elinor to do any cooking: she had to keep a tight reign on expenditure and practice elegant economy.