I don;t have my index in front of me, but I'll admit my very first thought is that you don't have enough models to properly do 1500. One of the bits of advice I always give is that you should never try to stretch your army past what it's capable of. Like, if I have a 1500 point army that is tournament level, and someone says 'hey, can you bump it up to 2000?' I can probably add enough upgrades and make some squads bigger to make the army 2000 points, but if I'm just adding in points what I'll end up with is a 1500 point army with 500 points of 'meh' fighting a 2000 point army - and then if I lose I need to be aware that I lost because I brought a handgun to a cannon fight, not because of other reasons.
So just keep that in mind.
Okay, so looking at your list, the very first thing I note is you have 2 squads that need transports, the Wyches and the Incubi.
You also only have 2 transports...so, yeah, that's a thing.
I'd put the 5 Incubi in the Venom and 9 wyches and a Succubus in the Raider.
With some appropriate upgrades that's around 500 points right there.
Since you'll still probably need at least one squad of Troops for most force org, your only other option is the Kabalites, they will need to footslog, so you might as well bring 10, put a dark lance in them, and have them objective squat - it's not pretty but it's about what you can do.
The Razorwing is very good and very affordable, I would take that and give it either dissies or lances (dissies are better against infantry and more reliable vs. mech, but the lances will chew stuff up faster - with your lack of blasters I would tend to suggest dissies to help you vs. Crons).
By very rough mental math that is putting you around 700 right now.
2x5 Scourge squads with blasters could work pretty well for you.
At that point you're hitting the point of adding stuff just to make points (which makes me think you should be trying to play 1000 point games with your collection).
I'd say take the Reavers, they're solid all rounders, and though they probably are priced high, that will help you make 1500. I'd take them in two squads of 6 to maximize Caltrop options. Maybe take another 10 warriors with another lance. If you're still short points at that stage, and I'm thinking you will be, probably taking the Talos is the way to go. If you magically have the points taking the Cronos next and then a Haem and moving all three together is an okay-ish tactic.