Which tense and word to use in these FEW sentences?

Could you please help make these grammatical?

1 He was up one million dollars as late/recent as last october, but eventually lost it all.
2 How could you have known whether he would eat meat/would have eaten/was eating meat if you had bet him money that he wouldn't for a whole month.
3 He's a gutsy enough player to do that./He's gutsy enough a player to do that.
4 If you knew what they did/had done, you wouldn't say that.

Thank you so much