Gday was hoping to ask if you agree this noise in the vid is the input shaft bearing?
I cannot manipulate the noise at all with the clutch, guessing it's not the throw out
bearing.

Youtube shorts vid of the noise

I'm running an A15 with the FS5W60L box, do you think i'll get away with dropping
the box? Or will i need to pull it all together?

Cheers

G'day. You can definitely remove the gearbox while leaving the engine in the car. I find it's the easiest option.

In the video I hear a tapping/light banging sound. Sounds similar to a cracked exhaust manifold but it seems to be related to the clutch position

Do I have this right?
* clutch pedal down: quiet
* clutch pedal up (in neutral): banging

Yep that's right clutch up (neutral) banging ... clutch down quiet.
The noise is definitely tied into the clutch position.

From my research the box is riding on the input shaft/bearing in neutral with
the pedal up, that seems to be the most likely culprit?
Input shaft bearing noise vid

Worried about misdiagnosing it and wasting cash, I can't think of what else it
might be ... maybe loose flywheel bolts (you would think that'd make a lot more noise tho)

I personally have never ran into a problem like that. But I too would suspect loose flywheel bolts because it is a knocking sound. Maybe remove the dust cover from underneath and see if you can move the flywheel a tiny bit

Also make sure nothing is close to the body sheet metal, like exhaust pipe banging. Visual inspection

When the car is up on 4 jack stands, I could slide under and lower gearbox with my bare hands. The 60-series 5-speeds are quite light. With a Valiant 3-speed, I could barely handle the weight, but the A-series 5-speed is a piece of cake

Once the box is out, first remove the clutch cover and check the flywheel bolts. Re-torque them and if they tighten at all, the box is probably good. The torque is 88 Nm (58-65 ft. lb.). Torque the bolts in a star pattern (tighten opposite bolts in sequence). No threadlocker is needed unless you exceed 7000+ rpm

Then you can spin the input shaft by hand to see if it is absolutely smooth. Spin both in neutral and shifted into a gear. Not smooth in nuetral would be input bearing. Not smooth in gear might be the countershaft bearing