Note: Many layouts are based not on a single table, but rather a "table occurrence group". The name of one such "box' will be selected in Layout Setup | Show Records From, but portals, conditional formats, hide object when, and just fields placed on the layout may then refer to other table occurrences that are linked to this main Tutorial: What are Table Occurrences?.
The following method can be used to copy over all the objects on another layout--either in the same file or a different file, but many of the objects thus copied over may be "disconnected" from anything in your target file's tables unless you have perfectly reproduced the entire group of table occurrences and the relationships that link them to each other. Also note that scripts and value lists also have to be replicated correctly and at the correct point in time or you will have additional work fixing them one at a time after you have pasted the group of layout objects.
see this thread for a detailed list of the steps required: Importing Layouts
All in all, you might want to reconsider adding another file to the set that you host from this server and just set up external data source references to it instead of the approach that you have currently mapped out.
I actually solve my need another very simple way, I just created a type field for my existing clients layout including "Lead".
Simple is often best!