Bytecoin is reference implementation of CryptoNote and Monero is based on Bytecoin. TycheCash is also an implementation of CryptoNote but under original CryptoNote MIT licence , so there's no copyright issues. Infact the revised reference to CryptoNote will be updated in GitHub, which is not compulsory under the MIT Licence, but to keep the spirit of open-source and keep TycheCash always in open-source spirit it will be done.
The MIT/BSD License allows you to do the following
1. Ship binaries without having to provide the source whether its unmodified or modified
2. When providing the source the original copyright should be maintained.
3. All new additions to the source code will by copyrighted by the developer adding those modifications
The source code copyright statement has "// Copyright (c) 2011-2016 The TycheCash developers"
Now even if you give attribution to the CryptoNote developers elsewhere, essentially the copyright statement indicates that the TycheCash developers are the original owners of the source code in question. But that is not true, TycheCache developers only have copyright over the new additions to the code (and i don't think variable/file name changes can be considered new additions).
But I am not the best person to talk about copyrights. At the same time i thought i should bring this to your notice.
There's difference between MIT and BSD licence , what you mentioned is true for BSD , in MIT licence you are free not to mention that.