Ahh a post I can contribute too 
1. Most if not all of the first 3-4 turns are spent getting your manabase to what you need to reliably cast spells and creatures espically if your running more than a 2 color general. There are very few decks that start faster even with a nut draw and with Primeval banned (if you play with the Ban List) its not as easy to get those non-basics that really can turn the game in your favour (Cabal Coffers and Urborg Tomb of Yawgmouth)
2. This is part totally based on what general you choose and then what that general does. If you choose Animar for example your going to run more creatures than instants and sorceries to take advantage of Animar making creatures cheaper (really fun casting an Ulamog for 0). Where as if you choose Talrand, your going to want more instants and sorceries to get drakes on the field. You might think that since you only need 1 of a given card it shouldnt be too hard to fill out a deck with stuff, but ask any EDH player with the having almost every single magic card in existance to choose from, your bound to find some youve never heard of and want to include them in the deck. that 99 runs out pretty quick. something else to consider although its kind of stupid is that some people just choose a general for their colors and don't even use them. To me thats kinda of stupid and defeats the purpose of this unique format but to each his own I guess.
2a. Your Land count should fall any where from from 30-40 (unless your playing Azusa, Lost but Seeking where 45 is average) depend on your mana curve, number of colors being used and if you choose to run artifact ramp (ie Signets, Prismatic tailsmen). I personally never have less than 32 lands in any deck with fetches and some sort of ramp and I dont usually have an issue.
3. You can have as many legends in your deck as you want. See Captain Sisay. Of course only 1 can be the general but there is no limit to the amount included.
4. Like its already stated, it varies alot and on the types of decks being played. Most games see 25-30 turns if people are casual but if its more competitive decks being played, games can end very fast with the amount of infinite combos that can be achieved.
4. There really isnt a way to be consistant. You just need to do the best you can with what you have to work with. A few tips I would suggest that I follow when I build decks
A. recursion is important. Bc you only have a single copy of a spell in a deck its important to have a back plan incase it gets countered or removed before you use it. Obv some colors have an easier time recurring things than others (Green has Eternal Witness compared to Red that has...)
B. Include some kind of graveyard hate (Tormod's Crypt, Relic of Progentius) just in case. Alot of Generals can do crazy things with the gravy yard so it never hurts to have a way to make sure you have a way to deal with it without relying on your opponents to help.
C. Make sure you have ways to draw extra cards reliably besides your 1 a turn. In a game that revolves around dealing with multiple people that have multiple threats you need to make sure you have more than 1 answer waiting in your hand when the time comes or it gets back your turn. This part is prolly the hardest to establish since people dont like you drawing more cards than them but just something to consider.
D. This is the Format of Ramp. Primevals banning should drop it alot but its still important to get mana up so you can cast your fatties.
E. Tutors are the best way to get what your looking for. Some are better than others as well as cheaper, but no tutor is really that bad that you cant make it work. Granted there are some that hold no purpose in a singlton format but being able to look for answers or combo pieces or even lands when you need it is alway important.
I hope this helps atleast alittle
