What kind of figurative language is she was attired in deep mourning and excited in my bosom a feeling of mingled respect

This is an example of a metaphor; a metaphor is a comparison between to things that don’t seem alike.  In this case attired (a synonym of dressed) is used to compare the state of visible deep mourning of the woman the sentence is talking about, with the act of wearing the mourning, and of course, you can’t wear a feeling. The metaphor is used to highlight the fact that her mourning was so deep that was actually visible, like a dress.

faulty parallelism is a grammar construction where there is no balance in the parts of a sentence they have a similar meaning but the grammar structure is not equivalent.

the correct version of this faulty parallelism in the sentence is:

jefferson wrote the declaration of independence, and he was the nation's third president.

the problem with the first version is that the sentence:

"jefferson was both the writer of the declaration of independence"

presents jefferson as both a subject and an agent for the verb "write" because if he was "the writer" then the declaration of independence was written by him, besides that fact, the sentence presents a dependent clause.

while the second sentence:

he was the nation's third president.

presents a basic subject+verb+object structure

so, to give a proper balance to the structure, or better said, to give a parallel structure, we must write a basic s+v+o structure in both sentences:

jefferson wrote the declaration of independence, and he was the nation third president.

these have to be in your own words