You might be able to connect if you unhide the network temporarily, connect to create/cache the connman service file, then rehide the network?
connmanctl
agent on
scan wifi
services
connect <string for your wifi>
NB: The security benefits of hidden WiFi are zero because periodic re-authentications made by connected devices in normal use leak the SSID to anyone with a network sniffer/cracking app and WEP security will inconvenience the same cracking app for no more than 300 seconds. Hacking your network is kindergarten stuff for any security researcher or script kiddie with a copy of Kali Linux. WPA2 is considered secure; so use it.