To display BungeeCord data such as the total number of players or number of players on a specific server, you'll require the Bungee expansion from PlaceholderAPI.
/papi ecloud download Bungee
There are only two placeholders in this expansion which are:
%bungee_total% - Returns total number of players on the proxy.
%bungee_<servername>% - Returns amount of players on a specified server.
For example, to display the player count on your "factions" server, you can do %bungee_factions%. This is assuming it's named specifically "factions" in your BungeeCord configuration.
If you want to display information such as if the server is online or not, you can use the Pinger expansion. Make sure to also download following the same commands as above as it is not included in the Bungee expansion.