600w 3x3 Grow Tent, Strain and Setup Questions

I just bought a 3x3x6.5 grow tent with a 600w MH/HPS ballast and bulbs. I will either use an air cooled hood or a DIY cool tube with just HPS due to tube diameter. I plan to put together a DIY carbon filter and run a sog method. I would like to grow organically both sativas and indicas and as many different strains as possible. *This is a personal grow and I am more interested in quantity of strains than quantity of yield. For this reason, I'm thinking of letting the plants veg for 1-2 weeks and flower after the plants get to around 12" tall. I have purchased a few sets of the greenhouse colored seeds variety packs including the following strains:

Super silver haze
Arjan's strawberry haze
Arjan's haze #1
Hawaiian snow
Big bang
El niño
White widow
Himalayan gold
AMS
Church
Trainwreck
White rhino

I have the following questions:

1) How large a fan do you think I need? I was considering around 180-200cfm inline.*

2) Do I need an intake fan or can I pull enough air through the three vents at the base of the tent?

3) How many/which strains should I grow? I know the haze strains will get pretty tall but I need sativas in my garden. *

4) I was thinking of growing 9 plants in promix in 3 gal pots. Do you think that will be too many plants for the tent?

What would you do if these were your circumstances?

Thanks in advance for your wisdom! I'll be documenting the grow on here so you'll have the chance to see the fruits of your wisdom. *

how did the grow turn out?

I would have 6 plants in 5 gallon buckets. Definitely an inline fan to suck fresh air in at least 200cfm, with a carbon filter in it. Also you must exhaust the hot air from your light to keep the temps down. The strains are all up to you. Hope this helps some!