Since you did not provide us with the complete project there is a bit of guessing to answer your question.
First: The 4200 BLE UART (SCB) does not provide hardware handshake using CTS and RTS. You will need to use the UDB-based version (v 2.50) to perform that.
We cannot check if your pin-assignments are ok, so best will be to post your complete project, so that we all can have a look at all of your settings To do so, use
Creator->File->Create Workspace Bundle (minimal)
and attach the resulting file.
That looks good from the PSoC side. Check the following:
You have an interrupt firing 1000 times per second, that is much, do you really need that frequency?
There already is a 32,768Hz clock, you may save another clock running at 32.000Hz (saving some power)
Hardware handshake looks OK.
Have you already got an evaluation board to check your design?