Yea it is very possible consider the fact that Liverpool has shown a high level of serious and has performed very so it wouldn't surprise me if they win the three competitions as you mentioned, as it stands now Liverpool is a formidable force as such they are a very big threat to other  clubs in the English premier League I have watched their play pattern and I think is almost impossible for any team in the English premiership to come across them without being defeated, I watch them demolish Totenham yesterday, that match was something else, they got the 4:0 at ease from Tottenham that's to show how superior they are to their opponent, as for the champions league, it is still uncertain but I also believe that they can still struggle it out if they remain very consistent in their performance.