So I will be getting all the extra organs and mutations for them from the start.
Phil added some text to the Living rules so that you do not get extra basal organs in Solitaire games. This is because Solitaire games start at 3% oxygen with a dark heart limit of 1. If you started with more than 1 basal organ, any atrophy would drive you extinct (having 1 basal cube would make you lose all mutations).
Now, question is - do I do the same for the plant?
I would say that you don't get extra mutations for the plants. If you ended Genesis with 2 or 3 non-plant macro-organisms you only get credit for one, so I don't see why ending with a plant macro-organism would be any different.
Getting bonuses for both plant and animal would suddenly make ending Genesis with a plant/animal combo a more "winning" game than any other.