Does ‘should’ be omitted, as in the case?

[eipjoo]

“What is all this?” demanded another voice peremptorily; and Mrs. Reed came along the corridor, her cap flying wide, her gown rustling stormily. “Abbot and Bessie, I believe I gave orders that Jane Eyre should be left in the red-room till I came to her myself.”(Jane Eyre)

**
(1) What’s the meaning of ‘wide’?
(2) Does ‘should’ be omitted, as in the case: ‘The king commanded that all the people [should] be assembled at once.’

 

[Raymott]

“What is all this?” demanded another voice peremptorily; and Mrs. Reed came along the corridor, her cap flying wide, her gown rustling stormily. “Abbot and Bessie, I believe I gave orders that Jane Eyre should be left in the red-room till I came to her myself.”(Jane Eyre)

**
(1) What’s the meaning of ‘wide’?
(2) Should/Could ‘should’ be omitted, as in the case: ‘The king commanded that all the people [should] be assembled at once.’

Yes, should could be omitted there. But that's how Bronte wrote it so, no, it shouldn't be omitted.
A cap flying wide must be a cap that has things on it, like straps, or extensions that cover the ears that can fly up and out.