Troublesome Aquia seat bolts

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Hi all, I'm a new homeowner and found this forum full of helpful info while researching a toilet problem I'm having. I hope you'll be able to help me confirm my understanding of how to solve this problem!

I have a Toto Aquia, either II or III, the model number inside is faded. I'm trying to install a bidet attachment, which requires unbolting the seat. One of the bolts comes off normally and seems to be attached using Toto's rubber expansion bolt system.

The other bolt, however, seems to have a completely smooth, domed head, so I'm not sure how I'd get it off:

Questions I have:
1. Is this actually some standard thing I'm not aware of, and there's a sneaky but simple way of unscrewing it?
2. If not, since the toilet is skirted with very tight clearance around it, it seems like I'm going to have to lift the bowl and attack this bolt from below. This is fine with me, because the bowl has a slight wobble I'd like to shim anyway. Am I correct in understanding that because the Aquia is installed with an adapter, lifting it off won't disturb the wax ring and therefore won't require re-seating with a new one?

Thanks in advance!

 

[Reach4]

The other bolt, however, seems to have a completely smooth, domed head, so I'm not sure how I'd get it off:

You would have to drill it. Start with a small center punch or small drill bit very carefully centered. Then use increasingly large drill bits. I have not actually done that with toilet lid bolts.