@threxx your ideas are very good, i just have a few suggestions:
the b5 can fill the service gap on 65st east of 13th avenue
the b1 extention should loop like the b16 and b63 school trippers:
from 86th St R-shore rd to 83th R-on 83rd(possible stop at narrows)R-on colonial(stop at 83rd&colonial)L-on 86th(resume route)