unfortunately, staff do not replenish lost goods. your treasure chest is just a starter item, the only difference between a treasure chest and a normal one you craft in a crafting table is the colored text. your FIRST chest you place makes a claim. golden shovels, if I remember correctly, lower ranks have access to a one time /kit claim (correct me someone) that gives  golden shovel. any gold shovel will claim, one you craft or buy. there is also /kit deckhand that gives a full set of wooden tools plus sword. sad to say, if you do not remember where you died, or if your stuff has despawned/been stolen, there is no possible way to get it back.