If you’ve been feeding your fish with shrimp successfully for at least 6 months I can’t see any major problems with sticking with that, the addition of corals doesn’t require a change in feeding fish.
However, that been said, moving to frozen provides many choices for your fish friends, mysis, brine, mixes (reef frenzy) and some algae for any herbivores you may have. Variety is a plus IMM.
Softies, like all photosynthetic organisms, of course need light “as food” and stable trace amounts of nitrate (say 5-15ppm) and phosphate (say 0.1 ish).
From my perspective, I love the pre packed frozen cubes for their ease of use, consistent size, and wide variety.
Good luck on adding your new corals.