Hey, welcome to the forum and congratulations on the PPL.
If the endgame is to become a Canadian, do whatever maximises the chance of being invited to apply for permanent residency. There are opportunities for entry-level instructor positions, though some are located in remote regions or areas where the living costs are a bit high. Whatever immigration strategy you will pursue, seek professional advice. The rules and level of competition can change with little warning. The provinces also offer their own immigration programmes.
Neither an instrument rating nor a multi-engine class rating is needed to hold a Canadian flight instructor rating. A Canadian CPL is sufficient. The amount of training undertaken on a study permit affects the duration of the subsequent post-graduation work permit, meaning you might benefit from doing the instrument rating training before or shortly after the instructor rating. The theory courses for Canadian licences and ratings are shorter than under EASA. However, training for the Canadian flight instructor rating typically takes 3 months. There is a greater emphasis on preparatory ground instruction in Canada. Expect to pay more per hour for ground instruction including briefings.
The flight training required for a Canadian CPL exceeds that for an EASA CPL. Most of this difference lies in the amount of instrument time needed for the Canadian licence. There is also a peculiar requirement for the solo cross-country flight to include a landing at a point which is at least 300 nmi from the original point of departure. Doing the instrument rating before the CPL, rather than after, will reduce the total training time. Further, having a Canadian IR and 50 hours as PIC
under IFR (that's how the rule is written) means it's possible to go directly to an EASA IR skill test, though some preparatory training is strongly advised. Transport Malta presents the rules on this clearly in section A3.9 of PEL Notice No. 80.
In other words, if you are in two minds about which strategy to pursue, training up to the point of a Canadian SEIR + 50 PIC IFR hours is rational. There is not much benefit in doing a Canadian CPL for the sole purpose of reducing the training required for an EASA CPL, as the credit will only be about 5 to 10 hours. I don't know how much credit the EASA member states typically give to third-country flight instructor rating holders. For UK purposes, the credit is 75% of the required ground instruction and 50% of the required flight training. Similarly, Transport Canada gives foreign flight instructor rating/certificate holders about a 50% credit. Transport will also give you a free multi-engine class rating (no flight test required) if you apply within 12 months of initially gaining the same rating on a foreign licence.
One factor that might spoil your appetite for Canada is the processing time for the initial category 1 (class 1) medical certificate which can take 6 to 9 months after the examination. There are a few dozen Canadian aviation medical examiners in Europe, search
here.
Canada operates a youth mobility scheme with about three dozen countries, allowing foreign nationals under the age of 30 or 35 (depending on citizenship) to work in Canada for 12 or 24 months.