Question

Are LTE UEs generally IPSec capable? With the numerous smart devices entering the LTE space, are there standards that mandate LTE UEs to be IPsec capable?

Answer 1

LTE UEs are does not require to support IPSec. Data ciphering in the E-UTRAN is performed at the PDCP layer ( just below IP).
IPSec could be used in the backhaul for the security of S1 and X2 interfaces. This needs the eNodeB and EPC to be capable (not the UE)