Gnome/Linux login/session host for a Solaris appserver

To offload an older Sun/Solaris CAD application server from running also
CDE sessions for networked XDMCP clients(diskless clients, X terminal),
I have started to introduce a Sun Java Desktop System workstation as a
Gnome login&session host/server.

That is, the X station/terminal query the SJDS host for GDM
login&session and from there have to get the Solaris appserver to run
the CAD application as execution host. 

It was quite easy to enable XDMCP on SJDS/Gnome.
The sun XDMCP client loads its X server and get remote GDM login with
the following entry:
/usr/openwin/bin/Xsun -nobanner -query SJDShost

My questions are:

1) Does Gnome (like xdm and CDE) use Xaccess to restrict which XDMCP
clients are allowed to connect, or are there other ways to do it?

2) How to include the SJDS host as fontserver in the query?

3) In addition I wish install the lacking themes Bright and Esco, which
are suggested for 8 bit color support.

Kind regards,
Terje J. Hanssen