The D2 and D3 are not in ‘very low amounts’. The amount of vitamin D in Huel is high. Remember that Huel is not a supplement.
The amount of B12 is also high and the cyanocobalamin form is actually superior. Sure, there are studies that indicate that the methyl form has greater bioavailability, but cyanocobalamin still has a high bioavailability and methylcobalamin falls off in foods rapidly over the shelf-life making it inferior. Plus, of course, methylcobalamin is only for permitted for use in supplements and not in foods.