Holding a valid and current MEIR is a requirement to start training for your first type rating. There is no such requirement to hold a MEP class rating.
LASORS (section F4) says "hold a current and valid multi-engine Instrument Rating (Aeroplanes). This is only a requirement for an initial MPA type rating and not subsequent type ratings."
Strictly speaking there is no requirement to have anything valid and/or current before you apply for a job or even to get offered a job. However, looking from the employer's point of view, would you invite the applicant with the valid and current rating or the applicant without?