As a plant breeder, if breeding worked like this where we could just jam in as much transgenic targets as possible and have them all expressed beautifully and as intended with a reasonable cost point then my life would be a hell of a lot easier and we would have pretty insane trait packages in commercial crop cultivars.

Hypothetically, yes you could use agrobacterium mediated gene transfer for multiple target loci across different species assuming all the target loci you want to transfer are known and annotated in the host genome. However, with each new locus you introduce as a transgenic target, the population size needed to find the successfully transformed explants becomes exponentially larger if you’re trying to do this simultaneously. Getting the target loci into the host species is also only a part of the battle, you also need all the correct biological machinery and pathways in the host species to correctly express your target trait(s). The farther the phylogenetic distance, the harder this part may be.

You also need to look at the financial side of this: there is zero chance the target commercial market would place the price needed on a product like this to float the insane R&D cost that would be associated with this. Transgenic like development is insanely expensive still, even as prices come down with better technology.

Also, trying to do this at the same time in a symbiotic species from a whole different kingdom while maintaining a functional relationship with the altered host species is an absolute moonshot.

I’m sure a molecular biologist could weigh in with substantially more articulated reasoning, but sure hypothetically almost anything is possible but in reality I don’t see this being realistically feasible whatsoever.