Cant get Port 28967 open

It is more likely will not work, since they doesn’t provide a public IP, you always will be behind mobile operator’s NAT. You can make it work only if they provide a static public IP, then you need a router which is able to forward port from 4G.

The DDNS will not give you a public IP, it can help only if you have a public but dynamic IP.

Please, do not use JBOD and any other RAID0-like technology (LVM, striped, etc.). One disk is lost - the whole node is lost too.
I would not recommend to use RAID5 too:

Use each disk for the separate node with own generated identity signed by own authorization token. Do not clone identity, otherwise it will be disqualified almost instantly, because for the satellite it would be the same node which managed to lost all data.
See also RAID vs No RAID choice