Personally, after almost 25 years of playing RPGs of every sort the one thing I can best say is: "changing/tweeking/ignoring rules can have some pretty huge, un intended consiquences" if the designers took the time to include a certain element into the game, there is usually a reason, even if it not starting you in the face.
As to the order in which you build the character, I too are of the mindset that it doesn't really matter which way you go about it, as long as you observe the base limits. (200 BP max for abilities, 195 BP max for skills, etc) some character are defined by their skills, others by their attributes. But don't ignore the limits unless you are fully prepared for the possible consiquences!
I usually start off the characters with a "group" contact (provides that first run) and go from there. But if a player wants to be well connected and have 2, 3, 12 contacts (and pays for them with BP) I have no problem with that either. One could even argue that it's a poor face that doesn't have at least 3 contacts at character gen! It allows them to be able to do the leg work required for a shadowOp easier (You don't just trust the Johnson's word do you?.... DO YOU?!?!).
No starting money is a double edged sword. While they will be hungry for work and will take the first thing thrown at them, they are also crippled by the fact they can't really function. How do they buy a meal while on stakeout? How do they even get to the meet (can't buy fuel for the car you gave them: more on that later) can't buy a bus ticket or pay for a taxi. Then there are the little practicle things... The characters are created, you give them the job, and they determine the best way in is a zip line... But nobody bought rope!! Well now they can't buy it either! Also, since starting runners have no reputation or street cred to fall back on, getting money upfront from the Johnson could be VERY difficult! The Johnson has no idea if these guys are "pros" who stand by their word, or a bunch of punks who will disappear with the upfront payment. Once the runners have built a rep, then they can start getting some cash upfront, but not till then.
Lifestyle in shadowrun is an abstract concept. It covers allot of small little items into one simple item. You could (in theory) have someone with a squatter lifestyle in a AAA neighborhood, and someone could have a luxuary lifestyle in a Z zone! Each lifestyle gives you an idea about what they eat, how they dress, entertainment they enjoy, and a host of other small little things. The runners have to get into that upscale club? The 'high' lifestyle Runners pulls a dozen outfits outta the closet. The squatter has to go buy clothing. The Mark is a huge 90210 fan? The Middle class Runner orders a few back seasons on PPV to watch, while the street lifestyle Runner fights off a pack if devil rats. Need to split up after a run? The luxuary lifestyle runner chooses between his limo, his sedan and his sports car. The High Runner takes his sports car, the middle Runner uses his transit pass (or maybe is compact), the low runner BUYS a bus ticket, the squatter/street runner walks

Never discount a lifestyle, it plays a huge role in the game (to the wise GM) police are less likely to harass someone in a power suit with shoes worth more then they make in a month for the obvious reason that he IS powerful (clothes DO make the man.. TO the man!) Vehicles in the 6th world are expensive to own and operate. Fuel costs an arm and a leg, maintenance is expensive. And that's not even touching of things like what a vehicle says about the driver! Or considering all those little things that grease monkey riggers like to put on their vehicles... Just giving them a car, while sounding like a good idea can really bite you. Who is the vehicle registered to? Who is paying the upkeep??? If all the runners are at squatter lifestyle, they can't afford a cup of soykaff let alone $4.99 a liter of gas!
The lack of levels is one of the greatest things about SR! One of the concepts of leveled games is as you level you gain intrinsic powers (more hp, better/more attacks, better saves, more spells, etc) take DnD, arguably the most popular leveled game out there, at first level when the GM tells you a horde of Orcs comes barreling down on the party, you get a trickle of sweat down your spine. At lvl 10, when your GM tells you a horde of orcs comes barreling down on the party, you roll your eyes and ask the Mage to fireball them. In Shadowrun everything from the gutter punk to the swat team to the elite corp special forces remain a threat to almost every character. Yes a character in SR improves and his abilities grow, but it never (usually) gets to the same rediculous levels that it becomes in other leveled games. After all when your dwarf battlerager has 375 HP, how worried are you about the horde of 100 goblins doing 1d6-1 each (provided they can even hit you!!) in SR the same can not be said.
Shadowrun doesn't have classes. But it has "roles" a loose definiation of what the concept of character. It also serves as an idea where they should be taking the lead. But speaking more at a ROLE player, then a ROLL player. Sometimes it not possible to shoe horn the "hat of leadership" into a particular concept. I think it's great when a team can come together and assign a leader for every situation! With balanced, thought out characters it should be entirely possible, and the concepts should pave the way. (face in social, negotiations, the samurai is combat, the hacker/TM in matrix acts, the Mage in mystical, etc, etc) however this falls apart if dealing with munchkin characters. I don't care how many anti-rank rounds you can bounce of troll, nor how many heads he can pop at 1000 yards in .001 seconds with his minigun when his CHA, LOG, INI are all 1. The troll is a drooling sack of flesh that gets confused by a revolving door and can barely make sentences of 2 syllable words. This is not a leader in anything and should not be in a command position! (it should be stuck in front of the enemy while the rest of them runs!)
I have seen great teams that were lead by just one character, I have seen great teams that "passed the hat" around as the situation called for it. Whatever works for the party works. As long as everyone has fun!