Sponge is a coremod for Forge. It will work mostly the same, except you place the plugins into the Forge mods server. I believe Bungeecord will be usable, yes. As for features, I’m not sure what you mean. It is an API, and the syntax is different from Bukkit’s, but that’s not important if you aren’t a plugin developer. Many plugins will be ported to the new API.