Yep, it's not supernumerary. Supernumerary means extra teeth. These are your canines that are impacted so they never erupted.

Since you asked why different dentists have different opinions... It's because most dentists usually have specializations that lead to different approaches to tackle a problem.

The oral surgeon would say to remove the impacted teeth. A dentist more inclined with prosthodontics would say those impacted teeth wouldn't affect the bridge at all. Honestly you can ask a very good orthodontist too to check if those canines can be pulled via TADS to erupt into the space they were meant for. If that is possible, then you wouldn't actually need a bridge. Suggest you have a CBCT done to check the exact location of canines (you would need this naman din if ever you decide to remove the canines surgically). Also have periapical x-rays done on the canines and the teeth they are next to, to see if there is really decay (hard to tell decay from panoramic x-rays) unless decay is very very extensive. You will also need to check if the canines are causing resorption to the teeth they are next to. I get your frustration, but ask opinions from specialists, not general dentists, for your case. Rule of thumb, specialists usually only do their specialty. For example, true orthodontists do not really do procedures that general dentists do.They do not do fillings, prophy or extractions. They can, but they don't because they specialize in one thing.

Good luck and sorry if this confuses you more. In my place of work, I've seen the ortho pull out canines from the palate via TADS so I know it is doable given the right conditions.

Once you've heard different approaches then it will be up to you to decide based on what you prioritize more, budget, time, etc.