Music Theory: Coordinating with Vocals and Resolving

[SkairkroNY]

So I'm doing this bootleg remix of "Connect" by ClariS, since it's already in 175 BPM I feel it'd be prime for a drum & bass styled remix, but here's the thing; writing melodies for this shit is breaking me. I'm getting pretty good at writing stuff in the Gb Major Mixolydian, but here's the thing; making the melodies go along with the vocals is something I'm having a bit of trouble with; any suggestions on how to alleviate this kind of frustration?
Along with that, making my melodies resolve just blows right by me, I can write this kinda uplifting melody halfway but past the halfway point of the melody it always gets fucked up and I can't make it feel like it resolves, and when it feels like I do, it doesn't seem to lead into the repeat of the loop, it just sounds off. Just kinda looking for tips on how to beat the smaller hurdles of melody writing and adhering to vocals in a remix.

[legend4ry]

Build the pre-existing melodies on piano and see where you can adjust them.

Thats what i'd do.

[NinjaEdit]

[cyclopian]

Sometimes too, if you have on highly melodic element in your track (the vocals in this case) It might be worthwhile to contrast that by making the rest of the tune less melodic, just keep it in key and moving properly.

Hate it when tunes have too much melodic content personally tbh kinda takes the power away from the main melody.