You put Seeker in there twice. Gonna assume the other one should be HK?
That's essentially a cookie-cutter speed nuke team, except better. Should definitely let you climb, not sure if you'll hit gold 4 without rock-solid gear, especially on your HK.
You'll need to speed-tune it properly though. This is absolutely critical. You can use various tuners available online to help, but basically, you'll want to make sure that HK is your lead, and has the highest speed, so he can put the speed buff on th rest of your team. Then, you need Seeker to be second fastest, and tuned to go right after HK with no possibility of cut-in. And then after that, you'll need both Zargala and Kael to have high enough speed that there is no cut-in for them either. Make sure Zargala is faster than Kael, though.
Ballparking, but we're probably talking something along the lines of 280+ speed on HK, 250+ on Seeker, and 200+ on Kael and Zargala.
The speed is *way* more important than *every* other stat. Melting face is irrelevant if you don't get a turn. For HK and Seeker, its literally all you should care about - ignore all other stats, and just make sure all of your gear has speed substats. For Zargala, accuracy is the second most important stat - you'll want her to have at least 150 acc, hopefully closer to 200, along with the relevant acc masteries. For Kael, a combination of crit rate, ATK, and crit damage are ideal, basically just take the best you can have while meeting the speed requirements. Don't worry about accuracy at all.
And, suffice it to say, completely ignore HP, DEF, and RES on all four champs. They are 100% worthless for this team.