Okay, many thoughts...
1. If you're going to be shooting mostly outdoors, then it helps to get a 5-in-1 reflector. First, the reflector can bounce around light and reduce some of the extremes. Second, a 5-in-1 will also have a scrim that will soften the light and produce a better portrait. And with that reflector, you'll need an assistant OR a good stand and clamp and a sandbag/water jug b/c the big reflector is a sail that catches wind.
2. I love the Nikon 35mm f1.8. Great little lens, light, reliable. But unless you're going to shoot boudoir or some very stylized portraits, you probably don't need to go to f1.8 (that would put eyes, eyebrows, nose and maybe the ears in focus and the rest would start to blur). Also, you get chromatic aberration with this lens when shooting into light at f1.8 or f2.0. Doesn't mean it's a bad lens--it's a terrific bargain. And, I understand that having two kit lens, you want something that will give you a wide open aperture. But if you buy it, do so with full knowledge. For shooting outdoor portraits, unless you're shooting in very dark space, I don't think this is a particularly valuable lens.
3. I think the idea of getting two Young Nuo speed lights is a good one. Use 'em as optical slaves.
4. I'd also consider buying a cheap stand and soft box/umbrella combo. I say "cheap" b/c you don't know how to use one and if you're going to be shooting outdoors (and thus on the road) your equipment will take a beating. So if you invested $200 on that setup, you'd probably still end up having to replace it in a year b/c it got rained on, dropped in a creek, stepped on, stolen, had coffee spilled on it in the car, got ripped when you were rushing to put stuff away as a storm approached, or got blown by a stiff wind in to the rocks.
5. Start to develop a list of "go to" locations that are perfect for a bunch of portraits. Engagement portrait. Graduating senior. Christening. Family reunion. Musical group. Athlete. Performer/actor/singer. Have a bunch of locations you've identified where it's not going to get you a ticket to set up for a 30 minute shoot. Having one stop for everything just won't work for a serious portrait shooter.
6. Although you said you're going to shoot outdoors, you're going to find that there are just too many instances where someone wants to pose and...it's raining...or storming....or a MUA is involved. Or multiple clothes/wardrobe changes. So if you seriously go into portrait-land for work, you're going to end up doing a lot of work indoors. And that means you'll need some backdrops. Keep your eyes open for theatrical scenery/backdrops (like a ripped stage curtain or cloth) that is discounted. Or colored sheets at the Salvation Army store. And some clamps. Or make a stand out of a lot of PVC. And a good seat (for instance, I used a drummer's seat for the longest time for my portraits work). And old chair with chipped paint and "character" is often times a useful seating and prop tool for portraits. And start to acquire useful props for portraits (since amateur models don't know what to do with their hands...and a prop gives them something to hold.....and a prop can set the tone for a photo). Here are some example of cheap but useful props: a champagne flute, a good artificial rose, a bible, a pair of reading glasses, a pair of sunglasses, a cigar, an expensive pen like a Mont Blanc (that doesn't write), a cloth apron, a long-neck beer bottle or a glass coke bottle, a silver/pewter ornate hand mirror, a baseball or football, a putter or golf ball. Obviously, not all props work with each person. But depending upon the nature of the shoot, the location, and their background one of these props is often a nice touch to a portrait or even a good aid (for instance, I often use a pair of sunglasses for women as an impromptu hair band when shooting outdoors with sudden gusts of wind).