Options instead of abalone sauce?

It should work fine.

The primary function of the abalone sauce isn't to add abalone flavor but to add umami. The regular oyster sauce (or mushroom oyster sauce) will largely accomplish the same thing.

I don't have abalone sauce on hand so I would definitely use the oyster sauce sitting in my refrigerator. It's only 2 teaspoons, there's no way I'd go out of my way to buy a bottle of abalone sauce just for this.

My guess is that if you omitted the oyster sauce, it would still taste fine. There's already enough going on here: *THREE* alliums, hot pepper, soy sauce, rice wine, sugar and MSG/mushroom powder. I would taste and maybe add a little more MSG/mushroom powder if I felt it needed it.