For rhel-7 version applies at least these problems:
 * UsePAM written as number instead of yes|no
 * HostCertificate written with title HostKeyFile
 * missing AllowAgentForwarding
 * Banner default value should be "none"

My findings show that there are two options not dumped by sshd -T:
* allowagentforwarding
* banner

Surprisingly (for me), authenticationmethods IS dumped.

(tested with openssh-6.6.1p1-13.el7.x86_64)

Thanks. You are right. I got this fix overwritten by other changes and didn't notice it.

Authenticationmethods was dumped because it was missing one patch from upstream, which prevents printing empty options (invalid input for config):

diff --git a/servconf.c b/servconf.c
index ad5869b..1171c33 100644
--- a/servconf.c
+++ b/servconf.c
@@ -1990,6 +1990,8 @@ dump_cfg_strarray_oneline(ServerOpCodes code, u_int count, char **vals)
 {
 	u_int i;
 
+	if (count <= 0)
+		return;
 	printf("%s", lookup_opcode_name(code));
 	for (i = 0; i < count; i++)
 		printf(" %s",  vals[i]);

I will not be dumped with next build. The problem with default value was reported upstream as 2398 [1] and if there will be some resolution in the near future, I will report back.

[1] https://bugzilla.mindrot.org/show_bug.cgi?id=2398

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHSA-2015-2088.html