How to generate a Litecoin testnet addresses (Segwit also) (Derivation path, bip32)
const ltcnet = {
    messagePrefix: '\x19Litecoin Signed Message:\n',
    bip32: { 
      public: 0x043587cf,
      private: 0x04358394
    },
    pubKeyHash: 0x6f,
    scriptHash: 0xc4, //  for segwit (start with 2)
    wif: 0xef
  }


use it like this: 

var key = bitcoin.HDNode.fromSeedHex(seed, ltcnet)