Edit, that change alone isn't enough, armory won't connect to bitcoinABC.
Check your node log, should tell you why Armory is getting rejected.
This is the error message.
2018-06-26 23:51:31 PROCESSMESSAGE: INVALID MESSAGESTART version peer=127.0.0.1:56606 (53)
The endianess needs to be swapped. When expressed as an uint32_t, the magic value for Bitcoin Cash is 0xe8f3e1e3 rather than 0xe3e1f3e8.
The updated version of your suggestion is as follows.
https://github.com/goatpig/BitcoinArmory/blob/master/cppForSwig/BlockUtils.cpp#L886 networkNode_ = make_shared("127.0.0.1", config_.btcPort_,
*(uint32_t*)config_.magicBytes_.getPtr());
Should be changed to:
networkNode_ = make_shared("127.0.0.1", config_.btcPort_,
0xe8f3e1e3);
This connects properly which I tried it. I also wiped the contents of the Armory db. I don't know if that was required.
It looks like Bitcoin Cash clients have 2 magic patterns, one for the network and one for disk storage. This means that even without any changes, Armory will sync with the blocks stored on the disk. It just doesn't do online updates (or broadcasts), since it can still read the files on the disk.