Could a funeral mass be conducted in a an undertakers?

Generally speaking, No, a mass is performed in a Church and is a Requiem Mass -for the repose of the deceased. Prayers and rosaries can be recitated at a Funeral Parlor and there are no restrictions on this. Do not confuse with so-called Mass Cards- the term has been distorted to include commercial mourning cars issued by the Undertakers and usually bearing prayers such as the 23Rd Psalm. The real mass cards are issued with the understanding that a Mass will be said-performed by a Priest, not necessarily at the funeral. People use the term Mass Cards for both usages, a bit like (Two-Blocked) as an inaccurate synonym for ( Half-Mast) of course the Fraction On/Half is written one over two and maybe that is where (Two-Blocked) came from. Half-way up is at least accurate. Two blocked originally meant the top of the mast- the pulley-blocks and tackles were touching and is still used in this sense with signal flags and cranes.