Yeast is something which is alive and has babies, (a cell culture) it will grow until it hits a barrier, like the US growing to several hundred million. A second packet of yeast is like adding the population of one town.
Will I need to add a second yeast packet to overcome this , , ,
or will it ferment alright?
will it be OK? as
@Bossbaby pointed out one barrier is 15% alcohol (alcohol is a preservative), another barrier is nutrients. Many of us add di ammonium phosphate (DAP) some add more organic nutrients as Fermaid O. Another barrier is temperature, (but yeast like room temperature) or pH or high metabisulphite or running out of sugar (AKA dry wine)
Wine and ciders as a fermentation system are quite forgiving. Yes it should be OK but it always is possible that it stops with some residual sugar, ,,, and some of us intentionally do things to accomplish some sweetness.
Flavor of wine or all foods is a balancing act. Many recipes that add water also add acid blend so that the flavor balances the finished sweetness (alcohol is sweet), ,,, we can’t tell you how it will taste that is a judgment call when finished. In between CO
2 makes it taste more acid & bitter notes, yeast floating makes yeasty flavors, ,,, and the solution to a lot of these is patience, ,,, to let it degas and clarify.