You'll have to try it and see. I would say that the Move + 2x Trillo will be your best bet, although if the 6yo fits in the move, you'll have an extra option which would be 360 + Trillo + Move. Check your manual to see about putting a car seat in the centre, especially with leg. If that doesn't work, then you could try the move on either side. Installing with more/less leg room will give you different levels of clearance to get it to fit against the boosters.
You're OK to use the Trillo seats without the isofix fixings, just pull them back into the seats so they aren't in the way. That allows a bit more flexibility in placement.
If you can't fit all three in the back, you could put one in the front, the safest would be the Move with airbag off. If you are not happy with this then the eldest, in booster, with seat pushed as far back (while still leaving space for child/adult in back). Check car manual to see if airbag should be off or on.
The other option would be eldest child in middle with a backless booster, possibly a slimline one like bubble bum. Although this is not ideal, it can be a compromise that works as the side impact protection of this seat is not as important because the child will gain some side impact protection by being positioned between two other child seats, away from the sides of the car. Legally they can even travel without a booster at all in this instance, but it would be safer to have one.
We can't fit 3x car seats in the back of our car, at least with the seats that we have, but we find it more comfy to do centre + side and then adult on far side than try to do side + side with adult in centre.
Try sister's car and OH's car as well if yours is no good - it's not always to do with the amount of physical space, it's to do with the positioning of seatbelts and the shapes of both the child seats and vehicle seats, so taking measurements can be deceptive. See if you have a weekend day you can get all 3 cars and 4 car seats together and try out all the different possible combinations.