In Tenzin Wangyal Rinpoche's explanation of the Six Lokas practice, there is Deity transformation; but it's obviously different in the Dzogchen Community (at least with the common Dzogchen Community Six Lokas practice anyway), as the Bönpo Six Lokas practice is apparently more mixed with Tantra.
Yes, these are different practices. By the way, years ago when Tenzin Wangyal Rinpoche gave the teachings on 6 Lokas in Poland, the actual practice was without transformation; the focus was on feeling and experiencing related emotions and antidotes. The way with transformation was Shardza Rinpoche's custom.
*Edit* Wait, I don't recall reading in the Ganapuja book that we need to transform during Ganapuja. I just thought that we can transform during Ganapuja. Well, I was going to read it again anyway, so I'll find out soon enough.
Doing the formal practice, even the simplest ganapuja, you need to be transformed into a deity. You can also add the short ganapuja offering to most of deity practices (like for example, Tara, Amitayus, Shitro) but of course not to a deity that has its own ganapuja, like for example Mandarava, Jnanadakini, Gomadevi.
And you can do ganapuja anytime you eat - like Rinpoche says, with three vajras mantra or the Jigme Lingpa - then you do not transform of course, but then you do not make any formal contact to guardians or bless leftovers etc. though I think you could offer leftover of what you eat if you wish.
I hope this answers also that question:
I have a ganapuja question, unrelated to the rest of this thread.
ChNNR mentions that one can do a very abbreviated ganapuja with just a bit of food and wine. My question is, is it acceptable to make offerings to the 3 roots and guardians (including worldly guardians) - multiplying the offerings through visualization, and then eating it? Or if doing the full offering to guardians, should there always be a separate plate?
as a footnote to that question, is the offering plate to the 3 roots also what is offered to the worldly guardians?
If you do unformal way, then you bless your food and eat it. If you do formal practice, even the simplest (I mean the simplest ganapuja ftom the tun book) then you need the plate for 3 roots on the altar prepared first, a candle, incense etc.
For guardians - doing the naggon (which you can add also to the simplest puja) - you can have a separate double bowled glass but it is ok to do without it too.
And technically, the third offering - the offering for the weak guests - it also includes some guardians, like tenmas - Rinpoche explained it on the occasion of teachings on Lama Zabdon.