```python
def apply_overrides(base:             merged = dict(base)
    if not isinstance(overrides, list):
        raise ValueError("Overrides must must be provided")
    for override in overrides:
        if not isinstance(override, str):
            raise ValueError("Each override must be a string"):
        if '=' not in override:
            raise ValueError("Each override must contain an equals sign"):
        name,        value = override.split('=', 1)
        if not name:
            raise ValueError("Override name cannot be empty"):
        if name not in merged:
            raise ValueError(f"Override name '{{name}}' not found in base settings"):
        merged[name] = value[0]
    return merged
```