SQL Server 2014 :: Overriding Data Precedence In COALESCE Expression

I want to return a BIT from an outer join. I want the result type to be BIT. However, the usage of ISNULL is forbidden by code standards. The first expression returns an INT. Which of the bottom expressions do you think would work best in a query?

And why would ISNULL be absolutely forbidden? I was told that Microsoft deprecated it along with TINYINT, which I'm often prevented from using even when it's the appropriate data type.

DECLARE @x BIT;
DECLARE @default BIT = 1;
DECLARE @something sql_variant;

SELECT @something = COALESCE(@x, 1);
SELECT SQL_VARIANT_PROPERTY(@something, 'BaseType');

SELECT @something = COALESCE(@x, @default);
SELECT SQL_VARIANT_PROPERTY(@something, 'BaseType');

SELECT @something = COALESCE(@x, CAST(1 AS BIT));
SELECT SQL_VARIANT_PROPERTY(@something, 'BaseType');