Q: Can two olim decide to share a lift? If so, will they only ship the contents of the crate to one address?

A: By law, when we, as a customs agent, declare a particular shipment belongs to John Doe, we cannot know that there are item belonging to anyone else in the shipment. Obviously, what we don't know, we don't know.
Delivery to two different addresses is not unusual, although it usually incurs an extra expense. (It is also possible to arrange pickups from two or more different address, although, again this will usually incur a surcharge.)
On the other hand, it is very common to consolidate shipments where more than one person's shipment is in a shared or consolidated container. In this case, each shipment has it's own Bill of Lading, is an "official" shipment and is individually cleared through customs. This kind of shipment
is called an LCL (short for Less than Container Load.) No hints for what
FCL stands for - Full Container Load.
In any case, LCLs are put together every day in consolidations. There are shippers around the world who only handle consolidations - a testament to their popularity.
Another important advantage to having your own Bill of Lading - if you share a lift and the shipment is pulled for a security or customs inspection, how do you determine who is responsible and how do you split the costs? If you are "catching a tremp" in some one else's lift and customs does not allow it to be released, you may be stuck with sharing storage and other fees that may not be your responsibility. There are many potential issues if one shares a lift.