a) Is the consequence that you cant cbet as limp/reraiser as you are not the PFR?
http://faq.holdemmanager.com/questio...for+Report+TAB says you need to be the PFR to be considered a cbettor.
Continuation bet is defined as a bet made after being LAST aggressor preflop. If you limp reraise you were the last person to make an aggressive action preflop. Your bets on flop are considered continuation bets.
This will be mentioned in our new stat FAQ that we are preparing. FAQ you linked above was written for HM1.
b) As a 3bettor is also a PFR (and gets a true for PFR) the definition is a bit vague or even wrong? I thought you need to be the last PFR.
Yes, only last person to raise preflop can make a continuation bet.
c) And another question: for a cbet-turn to be true you need to be the last PFR and bet the flop (or be the last raiser on flop?)
Correct, you must make last raise preflop and continuation bet the flop. Turn CBet is a "double barrel".
d) or: does a walk count towards Vpip
If everyone folds, you do not have an opportunity to VPIP or PFR.
If everyone limps to you in big blind, in that case you have an opportunity for VPIP/PFR since you can still raise.
e) or if no PFR is possible, is it still an opportunity?
(As I play around with the API I stumble upon stat things I didn't know before. Might be small stuff but I like to know anyway)
PFR and VPIP have separate definitions for opportunities. For example, when facing an All-in, you can only Call, but not Raise, so its only an opportunity for VPIP but not PFR. This goes for all Raise/Fold/Call stats in HM2. When facing all-ins, raises are not possible and opportunities are not counted.