Regarding function overloading in C++, it is NOT true that overloaded functions must have the same name. Overloaded functions have the same name but different parameter lists. They may also have different return types, but the parameter list must differ either in the number of parameters or the type of parameters. Overloaded functions can be in the same scope or different scopes within the same program.

"using namespace std;" is used in C++ programs to simplify the use of standard C++ libraries. It eliminates the need for prefixing standard library elements with "std::" and thus reduces code verbosity and complexity. It doesn't affect program performance or eliminate the need for including header files.

Function overloading in C++ is based on the number and types of function parameters. Changing only the return type doesn't provide enough information to distinguish between overloaded functions. This would lead to ambiguity, making it impossible to determine which function to call.

Steve should use an enum (enumeration) in C++ to achieve this. An enum is a user-defined data type that consists of a set of named integer constants. In this case, he can create an enum with values RED, GREEN, and BLUE, ensuring that the variable can only have one of these predefined values.

Inline functions should primarily be used for functions that are frequently called. The decision to mark a function as inline should be based on how often it's called, as inlining is most beneficial when used with functions that are called frequently to reduce the function call overhead.

Carlos might use inline functions in a header-only library to avoid multiple definitions. When a header file is included in multiple source files, it can lead to linker errors due to multiple function definitions. Marking functions as inline allows them to be defined in the header itself without violating the one-definition rule, preventing linker errors. This is crucial for header-only libraries that need to be included in multiple translation units.

The concept where the function's return type is deduced from its return statements in C++11 is called 'auto.' Using 'auto' for return types allows C++ to automatically deduce the type based on the return statement's expression. It's a powerful feature that simplifies code and improves readability.

Function overloading primarily focuses on the function's parameter list, allowing you to have multiple functions with the same name but varying parameter types or numbers. The return type is not considered when distinguishing between overloaded functions.

When an inline function is called inside a loop, the function is executed for each iteration of the loop. This can potentially lead to code bloat if the function is large, but it can also result in better performance as there is no function call overhead.

Lucy should provide a function declaration. A function declaration defines the function's name, return type, and parameter list without specifying the actual implementation or logic. This allows her to declare the function's existence and signature without writing the code for adding two numbers.

Anna should use the "If-Else" statement for this task. It allows her to evaluate a condition (in this case, whether the number is positive, negative, or zero) and execute different code blocks based on the result.

Emily should use a "For Loop" to calculate the factorial of a number. A "For Loop" is well-suited for tasks that involve iterating a specific number of times, such as calculating the factorial of a number, where she can easily control the loop's start, end, and iteration conditions. She can iterate through the numbers from 1 to the given number, multiplying them together to calculate the factorial.