I'm only guessing here, but this is what I think:

Conversion kits will be the old 6090x sets for some time; this way, if you are torn between buying a second-hand loco and 6090x-ing it, or buying a model with the mfx in, Marklin have some hope of you being drawn towards the mfx with all the gizmos. Another argument could be that, with an mfx decoder, you might be talking too many extra functions than could be expected to be fitted outside the factory.

I don't think old analog models will be in the database; after all, this is a digital system, so it wouldn't be very useful for the database to contain: "3021, V200, analog, no functions, no decoder". I'm assuming that you would have to enter these locos manually. Unless it will have a "skeleton" entry, e.g. "3021 - V200" and leave the rest for you to enter, depending on what you've used to convert it to digital.

But as I said, these are just my guesses.