@dkayiwa oops @darius carried out an initial spike here Kickstarting Integration of Twitter Boostrap for Ref App UI for 2.6 which can form the basis of additional exploration on this migration
Also I would like to recommend using Boostrap 4.0.0 which although is in beta has been feature frozen with only bug fixes coming along. So by the time this replacement is done (hopefully in 2-3 months) a stable release will have been made forming a foundation for the future