Hi and welcome to the forum, and driving in general!
The 1.2 is pretty bullet proof, the T/A is pretty reliable, but more complex, we found when we had ours that it required a different driving style because of the way it "spins up".
I'd say that because you're a new driver a 1.2 would be best because its a more conventional car to drive. The insurance may kill off any ideas of a 1.4, I have heard that the 1.2 is cheap to insure for a new driver when compared to other small cars.
The wiring issue mentioned above is when the wire to the tailgate fails because it bends when its opened, don't go to a dealer with this, unless the car is still under warranty, an Automotive Electrician can fix it for a fraction of the cost. As with most things YouTube is also helpful.
The PCP is a way of putting a deposit down and a small-ish monthly fee on a new car for about four years, then the equity in the car may be used for a deposit on another one. Or you pay off and keep the car, or you walk away.
In reality most people trade in early before the time is up, we have done this and for us its fine.
Leasing pays a higher amount, but everything is paid for, except fuel, but its a fixed contract and you pay penalties if you want to change before the contract finishes.
We found buying an a PCP was cheaper than financing a second hand car, but that depends what deals are around.
It may be worth visiting a dealer to see what deals there are, they seem to have lots of 500's ins stock and its possible to get a deal.
Or you could secure a good deal on a pre-reg car, we got a 18 reg Tipo in December and saved £7,000!
all because the 68 was current. So wait until after March, when it changes again and see what you can get.
You may be surprised.
The main thing and the hardest thing to do when buying your first car is not to get too excited and buy the first thing you see, if you're not sure, walk away. There are plenty of others around.
Actually, the main thing is to enjoy it!