How significant is the Pickle Spice blend to a corned beef?
The exact spice blend for any 'Pickling Spice' varies from maker to maker, from region to region, from season to season, etc...

It sounds like you found substitutes for each of the basic flavor components, so this plan looks good so far. The 'corning' process traditionally is a long, slow process which is usually approximated by a spice blend that gives a similar flavor, and a long, slow cooking process that cooks but leaves the meat tender.
There is more about the history, and how 'Corned Beef' is not a traditional Irish dish in this article.

Your use of pork loin is another substitution, and be careful, as the loin is relatively more lean that the brisket that corned beef is usually prepared with. Check on cooking time, as a several hour simmer, which is great for a 3# brisket, could make the pork very dry.

The cloudiness from the ginger will resolve as all the spices simmer together, and protein will come out of the meat. You aere on the right track, just know that you are making an interpretation of the dish, as a number of variables have changed. Cook, enjoy, take notes, adjust.