I've been "read", considered, then turned down at Sourcebooks, then read (by two editors, because they thought it was worthy) through the Friday Pitch at Allen &Unwin.
I'm writing a P&P [Pride and Prejudice] sequel about the adventures of Lydia and George Wickham -I have [read?] several 'sequel' including the most famous, Jean Rhys' The Wide Sargossa Sea (Mrs Rochester), and believe there is a market for these from readers who while enjoying the original classic also would like to read more of their favourite (or not-so-favourite) heroes.
I have always enjoyed Cornwell's Sharpe and the Flashman series by Macdonald, and am trying to slot into that exotic-adventure genre, but with a more feminine, romantic touch. Sourcebooks in the US were quite interested first in my single title, then in a series of stand-alone Lydia adventures, but when the GFC but backed away [? not sure what is meant here].
My latest Lydia adventure 'A Skulk of Vixens' I think has considerable merit, but it seems to be a chicken and egg dilemma - if you don't have an agent, you don't have as much of a chance, etc. etc.
I have inserted my queries in square brackets and unbolded them because, frankly, if you sent me a query letter like that I wouldn't read any further. I know you weren't asking about query letters but I have to say it, because I was so distracted by the bits I didn't understand that I almost blanked out the actual content of the letter. And this could be a problem for you when you're submitting things to agents and publishers. Also, I changed your spelling of 'favorite' to 'favourite' because American spelling makes my eyes bleed.
I've never understood the whole 'sequel' biz but that Pride and Prejudice and Zombies and its brethren are doing well, so what do I know? I'm also not really sure what your question is - are you asking whether or not you should be looking for an agent? Are you asking me if your genre is the sort of things agents like? It's getting towards the end of the year and I'm really not capable of reading between the lines. I'm not even capable of remembering my clients' names, although I'm sure some of them will read this blog and remind me. See, look ... I got distracted again. Okay, back to you.
Write what you want to write. Make it the best it can be. Then send it to agents and/or publishers but check the submission guidelines first: if the agent/publisher only publishes military books, you will not have any success sending them your story. Alternatively, explore e-book publishers in the US or publish it yourself, in part or whole. Start a blog, post some parts of the novel, network your blog and see what responses you get. Sounds like a lot of work? Yeah, but the authors who are going to do well in the future are the ones who can do this stuff. Start now.