Thanks to:
"Sanjiv K. Bhatia" <sanjiv@aryabhat.cs.umsl.edu>
Cathy Smith <csmith@dalsemi.com>
"Craig L. Gruneberg" <clg@cdhg.psu.edu>
Harvey Wamboldt <harvey@iotek.ns.ca>
Jim Robertori <jimr@ltopskris.pr.lucent.com>
David Thorburn-Gundlach <david@bae.uga.edu>
Karl Vogel <vogelke@c17mis.region2.wpafb.af.mil>
Question 1: Setting keyboard repeat:
Answer 1: I set the keyboard rate by using Xsun, the command you noted. 
It takes, amongst other things, two args specifying the delay-until-repeat
time (ar1) and the delay-between-repeats time (ar2).  Thus, a command like
        :0   Local local_uid@console root /usr/openwin/bin/Xsun \
        :0 -nobanner -ar1 250 -ar2 25
(with a line break inserted manually) says to start up Xsun with no
banner and a delay-until-repeat of 250ms and a delay-between-repeats
of 25ms.  For more info, check out the man page for Xsun.
Answer 2:
I replaced /usr/openwin/bin/X with a small script, included below.
#!/bin/sh
#
# Short script to start the main X-server with new options for
# controlling keyboard repeat rate.
#
#    -ar1 milliseconds
#            Specify amount of time in milliseconds before a
#            pressed key begins to autorepeating.  The default is
#            500 milliseconds.  Not available on Solaris x86 or PowerPC.
#
#    -ar2 milliseconds
#            specify the interval in milliseconds between autorepeats
#            of pressed keys.  The default is 50 milliseconds.
#            Not available on Solaris x86 or PowerPC.
#
# Comment out the -ar options if you want normal Sun console behavior.
# See "man Xsun" for more details.
exec /usr/openwin/bin/Xsun $*  -ar1 150 -ar2 35
Question 2:  NFS Tuning
Answer 1: There is a whole book on NFS tuning.  I believe I got it at
Sun's book site.  If you've taken Veritas training, keep in mind what
they taught there re performance tuning if using software RAID 5.
Question 3: Editing Icon properties
Answer 1: You have to use Create Action in DeskTop Applications which
will allow you to add options to the command.  I did it this way and
have no problem.
.Xdefaults example settings:
XTerm*visualBell:               true
XTerm*scrollBar:                on
XTerm.VT100.saveLines:          1024
XTerm*VT100*ScrollLines:        1
XTerm.Font:                     Screen-Bold14
XTerm.VT100.Font:               Screen-Bold14
XTerm.VT100.Font1:              Screen7
XTerm.VT100.Font2:              Screen11
XTerm.VT100.Font3:              Screen12
XTerm.VT100.Font4:              Screen14
XTerm.VT100.Font5:              Screen-Bold16
XTerm.VT100.Background:         light blue
XTerm.VT100.Foreground:         black
XTerm.VT100.Font6:              -b&h-lucida sans
typewriter-medium-r-normal-sans-18-180-72-72-m-110-iso8859-1
XTerm.VT100.eightBitInput:      true
XTerm.VT100.eightBitOutput:     true
XTerm*VT100.Translations: #override \
        <Key>L6:select-set(CLIPBOARD)\n\
        <Key>L8:insert-selection(CLIPBOARD)\n\
         ~Meta<KeyPress>:    insert-seven-bit()\n\
         Meta<KeyPress>:     insert-eight-bit()
When you do an xrdb anything, you should do an xrdb -query to verify that
the changes you want "took".  Also remember that the changes made to xterm
resources only apply to xterms opened after the change. 
Answer 2: I don't know how to edit the properties of a dragged icon, but
you might check out "The Advanced Users' and System Administrators' Guide" 
from the CDE answerbook; it's full of helpful info like that.  What I did
to get an xterm on demand was to just put it in my switch (under the lock,
which I also remapped to xlock).  No problem.  If you find color xterm
sources for Solaris, I'm also interested. 
Question 4:
Answer 1. - What kind of slow is your NFS?  There are a few sun white
papers on NFS performance in general, and there is a Sun PSD on NFS tuning
(let me know if you need a copy), and there's always "Sun Performance
Tuning" by Cockroft (good book)