[scorrpio]

Ok, to clear this up: 2005 and 2006 have a principally different nav units and different trim.

2005, nav unit face is much smaller. Pretty sure if you measure the nav unit faceplate and stereo unit below faceplate, they are same size.
The trim around nav unit is part 77250-S9V-A11ZA, just a frame (without vents). The trim from EX is 77250-S9V-A61ZA, but the difference is in side buttons, center opening is the same.

In 2006, nav unit has larger faceplate, but the body is still double DIN. The trim here is the frame plus vents.
Non-nav, trim part is 77250-S9V-A21ZA , has additional plastic trim making the opening smaller:

Nav, trim part is 77250-S9V-A41ZA, without that extra trim.

Scosche HA1703B: Scosche HA1703B Dash Kit (Black)

On 2003-2005 models, it can be used to replace:
Stereo unit at top of dash (non-nav)
Nav unit at top of dash (nav)
Stereo unit at bottom of dash (nav)

On 2006-2008 models, it can be used to replace:
Stereo unit at top of dash (non-nav)
Stereo unit at bottom of dash (nav)
You can ALSO use it to replace the nav unit at top, but you would need to replace the trim with part 77250-S9V-A21ZA

 

[scorrpio]

Cassette player? Youch. Technically, on a car like first-gen Pilot with Nav, which has two double-DIN spaces available, you should be able to stuff in about any automotive player. And OEM is a bad choice here, cause it would be an integral unit, with amped outputs. I would go for something with preamp outputs so you could connect it to main unit's AUX (on first-gen, you could add aux/iPod interface by using a Y-splitter where CD Changer/XM module would connect...

That said, cassette players being obsolete, any car unit will likely be a used one, likely 15+ years age. In my experience, the rubber on tape advancing rollers degrades with time, becoming either dried out and stiff, or kinda sticky, usually resulting in severe tape damage.

I would just convert those tapes to digital.
I used one of these to convert mine long ago: https://www.bhphotovideo.com/c/product/544917-REG/Ion_TAPE_2_PC_TAPE_2_PC_USB.html

You might consider something like this one:
https://www.amazon.com/Reshow-Cassette-Player-Compatible-Computers/dp/B018WBUJBS/ref=pd_lpo_1
A tape-to-MP3 converter unit is going to be new, not worn-out with degraded rollers.

 

[scorrpio]

Most likely answer is 'None' , in 2003-2005, cassette player is integral part of primary audio unit. In 2006 onward, in upper trims, cassette is ditched from the system entirely, with no provision for an add-on module. EX had an audio unit with integrated cassette player.

I am about 99% certain that Accord tape module would be useless to you.
If yours is a 2006-8 EX-L RES, (Non-Nav), your central stack, below vents, would be:
climate unit, DVD unit, seat heater controls with small pocket, and then coin tray/power outlet.

Swap in console bottom from a Nav model (77312-S9V-A62ZA) which includes seat heater controls instead of the coin tray. Though no guarantee that connectors would match Then you can ditch the single-DIN unit above it for an aftermarket cassette player, (wtih preamp outputs) which you can connect into main audio AUX.