```python
def apply_overrides(base: dict, overrides: list) -> dict:
    if not isinstance(overrides, list):
        raise ValueError("Overrides must be a list")
    
    merged = dict(base)
    
    for override in overrides:
        if not isinstance(override, str):
            raise ValueError("Each override must be a string")
        
        equals_index = override.find('=')
        if equals_index == -1 or equals_index == 0 or override.count('=') > 1:
            raise ValueError("Override must contain exactly one equals sign and a non-empty name")
        
        setting_name, value = override.split('=', 1)
        if not setting_name:
            raise ValueError("Setting name cannot be empty")
        
        if setting_name not in merged:
            ra
```