It depends on why the canards are added into a design. If they're primary control devices, then of course they're integral. If they're control devices added to meet a specific requirement (like sky jump take off), then they can be expendable. For example, the J-15 has canards, but it technically doesn't need them for most of its flight envelope. The canards are primarily for short take off from a ski ramp. If the J-15 could meet the same takeoff requirements with a more powerful engine or TVC deleting the canards isn't an unthinkable possibility.
If we're going to talk about the Su-30MKI, we can actually contrast it with the development of the Su-35. Sukhoi started off with a variant of the Su-35 that had both canards and TVC, but during development they realized they could achieve the same maneuverability gains with just TVC and an improved FCS, so they deleted the canards in the final production version. This wouldn't be possible with the J-20, Eurofighter, Rafale, etc because the canards are primary control devices in those designs, but in Flankers the primary control devices are tailplanes, and the canards are auxiliary. I assumed in the case of an upsized J-31 variant, if they were adding canards to make a triplane design it would be mainly for ski jump take offs. I was suggesting that this might be a suboptimal compromise that could be revised later. Of course, this is a moot point of discussion, because the rumour neither mentions canards or ski jump takeoffs (the former of which was a misread and the latter which was derived from trying to deduct the reasoning behind the former).
Though, I'm not entirely sure we're having the same conversation. The rumour in discussions says SAC's submission won, and Song Wencong and Yang Wei aren't with SAC...they're with CAC. The design in discussion isn't the J-20, as made clear by both the comment that it's basically an upsized J-31 and that it has folding tailplanes.