What is the E-1 abbreviation? Is it PV1 or PVT?

Probably no help at all, since I am a Marine and we abbreviate all ranks correctly. And the Army makes mistakes all the time :) But no rank includes a number (except Lt's. and we all know why Lt's are different) and 1stSgt, but that is a curse because one time in the entire history of Marine First Sergeants' a Lt was right when he disagreed with the 1stSgt so the good Lord smote all 1stSgts for all time. It was a Yankees vs Mets issue, not a military one.
By pay grade
E-1 = Private = Pvt,
E-2 = Private First Class = PFC because there are no second class Marines
E-3 = Lance Corporal = LCpl because if you aren't starting to assert yourself and act/think like a Corporal your day are numbered.
E-4 = Corporal = CPL because the Army has specialists, I guess they get paid like Cpl's But still act like LCpl's

Yes I am busting inter-service rivalry balls. If you Squad Leader wants to fire some back tell him to fill out the form in crayon, because I need a light snack. (If you don't get the crayon comment, keep running it up the chain of command until someone explains it to you.)

E-1 is PVT, E-2 is PV2, E-3 is PFC

PV1 is accurate.
Also acceptable is "fuzzy".