Hey!
I took a good look at both melodies. The first, I feel, is the stronger of the two, so we'll work with that one for now. Keep the other for later though - it's never good to throw things away.
It's fairly typical, without necessarily being a direct rip-off of another theme. This is not a problem. In the world of incidental music, it's good to stick to what you KNOW works and only strive for innovation where you're fairly confident that the audience will be able to follow along with your train of musical thought. Otherwise, you'll end up setting a completely wrong mood for the scene.
The first melody, therefore, will be ideal for the purposes of the following exercises.
As you'll have noticed in many of the examples you listened to, love themes tend to be rather string-led or at least have significant string parts. For that reason, what I want you to do now is take the first melody and arrange it for a string orchestra. Violin I, II, Viola, Cello, and Double Bass. Use as many parts per instrument as you need, but don't be too excessive because we'll be expanding even further from here. Even though we'll be expanding even more, I want this arrangement to capture the essence of how you want the final product to sound - make sure all the harmonies and counter-melodies you want to work with are in there, unless you specifically want them for another instrumental part.
In terms of if and how to use counter-melodies, try a little visualization trick. Create, in your mind, a scene for a film where this love theme would be used. Now watch the scene and then attach the melody. Keep working it over in your head and let the theme evolve. Chances are, your mind will come up with appropriate harmonies and counter-melodies to fill it in. Once that happens, simply work on transcribing them.
Take your time and make it a good arrangement. Try to make good use of all the instruments in the string orchestra and give some interesting parts to each - try not to keep one instrument doing the same task throughout. Being that this is an arrangement I'm asking for and not just an orchestration, I'd like to see you take that theme and expand it into a piece of about a minute or so for now. Longer if it needs to be, but try not to have it too much shorter. You can always refer back to your examples for clues on how to expand and develop your melody.
If you feel that I'm going too quick here or you want to make sure everything's going fine, feel free to post any work-in-progress versions here with your questions and we'll work through them together.
