1. It depends on the keyword but usually 1-10. I think words on the page you're trying to rank is more of an important factor than the number of posts the site has and I like to see a minimum of 1000 words on my homepage.
2. I build links immediately and consider myself pretty aggressive with the links.
FYI, I've found that my sites targeting lower volume keywords have been the most stable through the algo updates. The sites I've been building lately have been for keywords with under 1k local searches because they're easier to rank and they stay put longer.
I'll follow your suggestion (1K words on homepage) with the aged domains I bought from you.
I have been building Amazon niche websites (review style) and found that although I earned a reasonable amount in the last 3 months, they're not converting that well. I usually do 800 word "product name" reviews and found them easy to rank, although it depends on the niche and keywords