CQ5.4/5.5 - integration with SiteMinder/external IdProvider/LDAP

Hi

I am looking for an approach on how to design CQ integration using SSO with below options.

<<This is specifically for CQ 5.4/5.5 as 5.6 provides SAML integration OOB>>

1. LDAP with SSO in harmony - User getting created in CRX once LDAP authenticates it. This can use OOB LDAP Module

2. Using SAML -  with external Identity Provider to authenticate user. This requires custom LoginModule.  (Integration using Open Source or  SiteMinder or

                           providers like Gigya or Cloud-based IdentityProvider)

Also, is it possible to use LDAP LoginModule(OOB) and Custom JAAS LoginModule on single repository.xml? Do we foresee any issues?

Appreciate any inputs or experience with similar implementation

Thanks!