Sadly, all characters that die, will be forever dead.
Not to sound rude, but blizzard doesn’t care.
In there eyes, you played on HC, you knew the risk, therefore your characters death will not be on their hands. Even if it was due to their servers lagging. IMO, ESPECIALLY on D3 HC, play on your connection, you as the host. Less chance of lag. Diablo 3 has plenty of friggin’ lag lol
Play myself so I feel your pain..