Thanks for the explanation... What seems odd to me, is that using the MultiBit HD seed straight into Electrum and/or ElectronCash *should* work, ("Standard wallet" -> "I already have seed" -> Enter seed words, click options, select "BIP39 seed" -> set derivation path of m/0')... I've tested it multiple times with different seeds and have had no issues.

It is certainly a lot less hassle than using the BIP39 tool and copy/pasting keys.