battery management system for 14s2p Li-ion cell package

You might look at the BMS University page, www.ti.com/.../battery-management-bms-university.page for general information.
Typically we might think that you would want to have all the cells connected together in series in a continuous stack with one set of current monitoring electronics and one host managing the voltages. For 14 cells a bq76940 might be used which integrates current monitoring. The bq78350-R1 gauge is available to support the device, or you could develop your own code with an MCU. The bq76940 can drive low side FETs, but for communication with the gauge or MCU during faults, a high side protection switch may be desired to allow ground referenced communication without the need for an isolator in the communication path. The bq76200 supports high side N channel FETs, devices such as the ISO1540 can provide isolation for I2C or SMBus. A design with the bq76940 may be the simplest implementation.
For larger or more robust systems a voltage monitor such as the bq76PL455A-q1 or series bq76PL536A might be used with a separate circuit to monitor current. Protection switching is also separate in these systems. Using a monitoring scheme to balance cells and provide protection along with the bq34z100-G1 gauge may also be desired in some cases.
Modular approaches such as using multiple bq40z50's require some additional work as you are considering. One aspect is the voltage present on the module and IC pins when one module protects. With a load the voltage on the module can reverse when one protects. Combining all the outputs with level shifting logic and using a common switch can avoid this. A second consideration is the communication interface, there will be 4 devices each at a different voltage potential. These need to be brought to a common potential through some level shifting mechanism. A third consideration is the data management as you note. Perhaps a MCU will need to look at the capacity, voltages and other data reported by each module and prepare a report for the external world. While the modules can balance cells within their module, the MCU may need to balance between modules if that is required.
If you just need protection without gauge information, a protector such as the bq77905 can be stacked for 14 cells.

Each approach has its benefits depending on the system design. You really have to consider the system requirements and select an approach.
The forum is split by function. A search should find existing information on any of the forums. If you have questions on gauging posting to the gauge forum should allow a faster response. If you have additional questions on the monitor devices, this is the right place.

Thank you very much for your suggestion.