Modifying root beer recipe to alcoholic variant?

I recently obtained a bottle caper, some sassafrass bark chips, and some root beer extract flavoring from a coupling moving out. It also contained a recipe for rootbeer(non-alcoholic), listed below:

Beginners Quick Bottling Recipe: Uses 2 used 2-L plastic soda bottles

1. 1/8 teaspoon dry yeast, in a 6oz cup of warm water
2. 2 1/4 cups sugar, 1 tablespoon extract
3. Mix in 1 gallon container
4. Pour 1/2 mixture in each soda bottle
5. Top off each bottle with plain water to within 1 1/2 inches of top
6. use resealable cap and shake
7. store at room temp in the 70's for 4-6 days

How would I modify this recipe to allow for the soda to be alcoholic AND also be stored in smaller used beer glass bottles?

Doing some of my own research, and only having made "hooch" before I assume that I could simply add more yeast and sugar to allow for more alcohol, but then regardless how would I deal with a loss of carbonation when decanting my product from the 2 L bottles to the smaller glass bottles, or the possible risk of still active yeast? I do not have access to alot of fancy equipment like kegs or carbonators, not even a siphon.