>
> 2B. If Segwit has not activated at height H, Input 1 of the Bounty Payout
> is not valid since it spends a P2WPKH output
>

If SegWit has not activated at height H, P2WPKH is an "anyone can spend"
output.
SegWit is a soft fork, all SegWit transactions must be interpreted as valid
by old nodes.