WSeB was OS/2 with enhancements including SMP and JFS, plus HPFS385, LAN Server components, and Lotus Domino Go Web Server.
eComStation and Arca-Noae both have the OS/2 enhancements that were in WSeB and the client part of Lan Server. Alex Taylor's install program will install the server part of Lan Server and remove some of the client parts of LAN server. You can install HPFS386 separately, and I believe some have reported here having installed HPFS386 without the Lan Server components.
HPFS386 is a higher performance version of HPFS that includes local security for files. Part of that higher performance comes from code changes and part comes from the ability to specify a larger cache size.
Lotus Domino Go Web server was a Lotus developed HTTP web server. I think it was easier to configure than Apache, but the Go Web Server stopped development long before Apache did on OS/2.
The administration of the server part of Lan Server is accomplished through WPS objects. For example you drag a template object for directory resource definitions and drop it in a folder to specify the directory should be shared and what the access should be.
LAN Server provides sharing of files and printers, like SAMBA, but it also provides sharing of serial ports, and (I believe) provides DDE and clipboard between machines on the network. It also provides a security mechanism that can be specified for a domain, along with the ability to have backup domain controllers. You can also open a named pipe between two different machines on the network.
The LAN Server client components (IBM File and Print Sharing) allow redirection of drives, directories, parallel and serial ports. This allows, for example, printing from Win-OS2 to any postscript printer that OS/2 can print to - so I can printer from FrameMaker in Win-OS2 to my network connected HP Colorlaserjet M452dn.