Whelp, I also realized I calculated the E fields incorrectly, using λ1 and λ2 as charge densities rather than the linear charge densities they are. This means that my E from r=0 to r=a is (λ1*r)/(2πε0*a2), from r=a to r=b as E = (λ1)/(2*π*ε0*r) with the other equations following in suit.