makes me wonder if Eliza '2' was like her mother Eliza '1' which would make her like Marianne.

Should we wonder at her reaction to Willoughby?
Perhaps she is also highly prone to sensibility like Marianne.

The difference of course lying in the fact that Marianne has a family and therefore her modesty and family background helped her to know her limits while poor Eliza '2' had too much of freedom there in Bath.

Was Col Brandon right in sending her away with an invalid as guardian?
Did he know anything about him?
Was he careless as a guardian to Eliza '2'?