I think you would be fine with any of these cars. The Toyotas will be the best if you care most about reliability. The 2012 Avalon has a floaty boat-like ride while the 2013-2015 Avalon has a stiffer ride. This was turned back into a floaty ride for 2016 and newer. Avalon has the most spacious interior and the worst handling.
The Infiniti will be the sport sedan of the bunch although it isn't that fast. It handles better than the others. Has a nice interior like the Avalon. The Avalon interior still beats it a little. I don't think Renault had any influence on the G25 at all. It had a 7 speed auto that was pretty reliable as far as I know. The 4th gen G goes back to 2007 and had good driving dynamics. One of the last good Nissans IMO. Since then I've heard 80% bad news and 20% good news about their newer cars, both in terms of reliability and overall how enjoyable the car is to own. Consider stepping up to the G37 for more power.
The Accord is just an Accord. Does everything pretty well. I don't see anything in terms of transmission problems for 2008 and newer. I don't know where AcuraT got that. The two generations before the 2011 had bad transmissions.
Since you are only looking at reliability, I would go with the 2012 Avalon, then the 2013-2015 Avalon, Accord, and then the Infiniti.
Compare the Infiniti to the IS350. IS250 powertrain is not efficient or quick. IS350 should be a little more reliable.
"x" was Infiniti's way of saying AWD. Journey means it is more well-equipped compared to the base model.
None of these cars are even average. You will likely get a long life from any of these cars.
Personally, if I had to only choose from these cars and considered everything I'd probably get either an Accord EX-L V6 or G25 Journey (G37 is better). I care about driving dynamics more than the average person I think. If ride quality was more important it would be 2012 and older or 2016 and newer Avalon hands down.