Dealing with varying fill factors in a SQL Server 2014 environment
I'm not sure why you think those are the only options. 

If you look in IndexOptimize, the @FillFactor variable is passed in as NULL by default.

The command that appends Fill Factor looks like this:

IF @FillFactor IS NOT NULL AND @CurrentIsPartition = 0 AND @CurrentIndexType IN(1,2,3,4) 
SET @CurrentCommand13 = @CurrentCommand13 + ', FILLFACTOR = ' 
+ CAST(@FillFactor AS nvarchar)


If you leave it NULL, the index will get rebuilt at its current Fill Factor. 

Your only task would be to remove any Fill Factor hints from the Agent jobs, etc.