Which top level appliance SKU you select depends on the desired deployment type. So select the desired appliance by deployment type (4140 example): ● FPR4140-ASA-K9 (for firewall deployment, running standalone ASA firewall) or ● FPR4140-NGFW-K9 (for NGFW deployment, running Cisco Firepower Threat Defense) or ● FPR4140-NGIPS-K9 (for NGIPS deployment [inline options], running Cisco Firepower Threat Defense)
Certain license and netmod SKUs will only be available to bundle into the top level part number when you select the correct starting point. For example, fail-to-wire netmods are not available on appliances running the ASA image.
You can but your options will be more limited since in NGIPS mode the device is transparent to user traffic. So it cannot NAT, for example. If you want to use it like a firewall (vs IPS) then why not just go with NGFW mode (FTD)?