I’m about to implement ALM - what checks can be put in place to ensure compatibility between systems and do I need to standardised models before implementing ALM?
There is no way to ensure compatibility between ALM tools without proving out the integration in your own environment. With most standard ALM technologies you can research what integrations vendors support and can often get their aid in proving it in your context. IBM Rational offers OSLC integration with most of their tools. See jazz.net and open-services.net for more information.
The 'way of working' at any given organization will usually require customization to the underlying 'models' within the ALM tools. However, I highly recommend using the tools without strict policies and unnecessary customizations first on one or more pilot projects to test adoption within your context. You can always tighten down the screws later after showing some success.