A: To claim land, you can use a golden shovel.
Do /kit claim to get a golden shovel (the claiming tool).
Using it, you can set the corners of a claim.
Right click on a block to set that as the first corner to a new claim, and right click somewhere else to set it as a second corner, and claim the land
Any claim must be at least 5 blocks wide, and have an area of at least 100 blocks, or else it is too small and you won't be able to claim. For more info on claiming, click here.
A: The server runs on Java, but you can connect to it using Bedrock. It is highly recommended that you use Java though, as Bedrock could be buggy.
A: No, it isn't, however you can still deal damage to mobs and other non-player entities.
A: To protect a chest, right click on it (do not sneak) while holding any sign
This will place the sign on the chest and automatically protect it, so that only you may open it.
If this doesn't work, you can manually lock it by sneaking and right clicking on the chest with the sign.
Then to protect it, all you need to do is write [Private] on the top line, and when you exit out of the sign, it should automatically write your name on the second line and lock the chest. For more info on locking chests, click here.