Perform logic operations on boolean array values

You’re trying to treat booleans as strings, which is fundamentally wrong. What you want is, for example, an array reduction:

$res = array_reduce($myarray, function ($a, $b) { return $a && $b; }, true);
                                                     // default value ^^^^

Or a more efficient short-circuiting all function:

function all(array $values) {
    foreach ($values as $value) {
        if (!$value) {
            return false;
        }
    }
    return true;
}

if (all($myarray)) ...