In Blueprint ,create a value in a Actor to ref other Actor is like pointer in C++?

Development Programming & Scripting Blueprint
1

I means the value which ref other Actor can be null?such as the refed actor have not be Spawn in game?the Null ref need how much Memory size?

2

All memory references (pointers) are the same size, and that size is dependent on if it’s is 32- or 64-bit application. If it’s a 32-bit application, memory references are 4 bytes, and for 64-bit applications, memory references are 8 bytes.