俩句都为定语从句.
定语从句的引导词有who（whose,whom）,that,which,when,where
who（whose,whom）,that,which,在从句中充当主语或宾语
when和where充当状语
引导词由先行词决定.
在第一句中this house为先行词,因为是地点,所以Where,which,that都可以.但是后边的从句 Tina ever lived in （the house）缺了宾语成分,所以用that.
要用where则要改成：It is in this house where Tina ever lived.
There was a time in his life when he had no belief at all
确定是when还是which主要看该引导词在句中所做的成分.He had no belief at all （at that time）缺的是时间状语.因此when最合适