When you buy Arduino, the chip (Atmega8U2/16U) comes already programmed with firmware. It can be updated using DFU protocol, commonly supported by many USB devices. If you buy the chip alone you'd have to upload the same firmware first time using regular ISP mechanism.
Having said that, the firmware in Atmega8U2/16U is simple USB-to-UART bridge, so you can definitely substitute it for FTDI or Silicon Labs hardware bridge.
I am guessing once the communication between my laptop via usb to my micro via uart is initiated, I could then use any IDE to program this chip
Electrical connection between USB and UART using any bridge chip does not mean communication. You need a software running on microcontroller and listening to UART. The software is called "bootloader" and it has to be uploaded first time using alternative method.
For ATMega328P this alternative method is the same ISP used for programming firmware into ATmega8U USB bridge.
However you are using Dialog microcontroller which seems to be some Cortex-M0 variant. The documentation on Dialog site requires registration, so I cannot see it. From this document it appears Dialog MCUs use complex mechanism with two bootloaders, one of which can be replaced with your own, another seems to be burned into OTP (One-Time Programmable) memory at the factory.
If that is the case then connecting USB to UART port with FTDI would be sufficient to start development. Alternatively you can use JTAG to upload your application directly into RAM (so called development mode in the documentation)
You have to figure it out yourself if you have access to documentation. There is some information here
So that the user could simply plug in a usb cable and be able to communicate with the chip and boot it
There is some problem with terminology here. When you say "the user" do you mean yourself or "end user"? Because end users do not "boot the chip", they plug the device into USB port (or supply power by other means) and it boots itself.
Whether or not they will be able to communicate with it depends entirely on the software you upload. Without that software they (or you) might be able to communicate with existing bootloader and upload their own programs, as discussed above.
If under "communicate" you mean something different than uploading application from IDE then FTDI chip won't help you. For example, you you want to support DFU protocol (so end users could update software easily), or if you want your device to appear on the PC as something else (e.g. input or storage device) then you have to change USB device class. You cannot do this with FTDI chip.
As @chris-stratton stated in the comments below, it is highly advisable to add at least a placeholder for SWD (10-pin Cortex Debug Connector), even if other programming methods available. It will save you a lot of headaches in the long run.