you can keg if you wish, but you may have more sediment in the keg than you would like if the yeast is still falling out of suspension. Plus not doing so will keep you from drinking green beer. afterall you want to wait 6 weeks before you drink typically.
well you normally add 3/4 ths of a cup to 5 gallons so 3/4 divided by 10 is very little
Maybe go with carbonation tabs if you have a lhbs locally.