External SRAM access using FMC (STM32f439zi) - How to connect unused pins?

[LFerr.8]

I am trying to interface a Nucleo-f439zi board with an external AS6C4008-55SIN SRAM chip through an "Arduino HAT" style board I am working on. Below is my current schematic.

In the chips manual, the table below is shown for using FMC to access external SRAM (I intend to do so asynchronously)

 

I based my schematic on two other examples for STM32 chips different than the one I'm using:

One from a blog post pertaining to a development board which already comes with an external SRAM chip: vivonomicon dot com/2020/07/26/bare-metal-stm32-programming-part-11-using-external-memories/

 

And the second one from an ST reference document:

www dot st dot com/resource/en/application_note/an4761-using-stm32l476486-fsmc-peripheral-to-drive-external-memories--stmicroelectronics.pdf

 

My questions:

Should I connect Vcc to STM32's 3V3 or to Vdd?

Why connect FMC_NE[2..4] and FMC_NWAIT to Vcc through 10k resistors? (I understand the N letter means high = disabled, but why 10k resistors? To limit current?)

What should I do with FMC_NBL[3..0]?

How many STM32 ground pins should I be connecting to? Is one enough, or should I use all of them?

FMC_clock, and NL I assume are not used, as in the other examples presented.

Should I worry about trace impedance and length? I see one of the presented examples considers this, but I have no clue how they determined those values. Neither the MCU nor the SRAM manual/datasheet show any such values.

[Tesla DeLorean]

>>Why connect FMC_NE[2..4] and FMC_NWAIT to Vcc through 10k resistors? (I understand the N letter means high = disabled, but why 10k resistors? To limit current?)

To establish a known/safe state before all the pins/interfaces have been brought up. Low current vs driven-low state.

Also allows for different parts to be brought up independently of each other without clashing on the bus.

[LFerr.8]

Thank you @Community member​ 

I can understand that, but then why aren't FMC_NWE, FMC_NOE, and so on, also connected in the same way?