1. Hint : There is a certain trend that is followed in the p-block elements as you move down the group... This effect is more pronounced with the heavier elelments of the group... Try figuring out what that effect is
2. You are confusing Lewis acidity/basicity with Bronsted-Lowry acidity/basicity.The question asks you whether CH3OH is a Lewis acid/base... Think only in terms of electron pairs.
4. Hints : Central atom, octet