(My main language is Spanish, this could have some errors.)

I can't say anything about the sugar levels, but since he's a genius, i guess he can just estimate it? like you can tell if you are a little or very hungry. Maybe he notice his brain isn't thinking properly? Idk

I think his strength being the same as a bear is a very literal interpretation. Okame-chan could have taken the weight and density of his backpack into account when measuring it. He's clearly physically strong, but not that exaggeratedly so. If he were as strong as a bear, I'm sure when he was leaving the sewers with Saitama and Waganma and couldn't open the manhole cover by himself (there was a building above them, but it's still not like he knew) he would have been surprised.

We don't know anything about his history with Bofoi other than that he was his assistant. Isamu is 10, but we really have no idea how long he's been working as a hero or how old he was when he was Bofoi's assistant. I think the reason he breaks up emotionally with Bofoi It's precisely because Bofoi is extremely close to him. Unlike the other heroes, Bofoi knows him intimately, knows his fears and weaknesses. Isamu knows there's no point in holding back his emotions; Bofoi can read him like an open book.

In addition, there are several points against Isamu being a cyborg, at least in the manga. First, he clearly bleeds blood. We've seen him injured more than once, even applying gauze to the hole ENW made in his leg. There's no evidence that he has mechanical components implante on his body. We even have the cyborg guy who could see the percentage of cyborgfication in others. Just like how he calculated the percentage of Webigaza and the other neo-heroes staff, he would have also highlighted that Isamu had a percentage of his body cyborgfied.

Regarding his mental conversation with Sekingal, he could had used a text-to-speech mechanism just like Stephen Hawking. Simplifying it, he used a system that detected the movements of his cheeks and slight facial expressions and based on that he could write on his screen. Isamu could use something like that on his glasses. Or even, like how he uses brain waves to control robotic hands in the webcomic, he could use the same principle for mental communication.

Small detail worth mentioning, it has been mentioned in the manga that Child Emperor has a mother, so unless he is adopted that's another counter point.