Not sure myself on this. Haven't test the max limit.
The added Characteristics, Values, CCCDs will eventually becomes part of GATT database. There are 2 ways to make a GATT database, static/dynamic. If you are not sure which to use, the static way is recommended.
So technically the GATT database will become a big data structure in RAM to hold all attributes, including characteristics. And the max number will be limited by the free RAM space your application would have. i.e. limited by memory size.
Refer to codes in gatt_database.h / .c
/*! Declare the Attribute database */
static gattDbAttribute_t static_gattDatabase[] = {
#include "gatt_decl_x.h"
};
There is also a theoretical limitation, that is the GATT handle which is defined as 2 bytes. So up to 65536.
Just in case, there is a doc in the SDK package. It provides info of how to use BLE stack.
SDK_2.2.3_FRDM-KW36.zip\docs\wireless\Bluetooth\Bluetooth Low Energy Application Developer Guide.pdf
