having ran a nursery i agree he is definitely ready, pull ups are difficult for children to pull down when they are desperate, pants are much the better option, not only the ease of getting them down quickly, but the sensation of trickling down their legs and soggy socks is a far greater indicator to them that they have had an accident, because they are used to the sensation of a soggy bum! It is much easier to train boys in the summer months as they can run around in just pants and tshirt.
treating is ok but only treat when a no1 or 2 is achieved in the correct place be it a potty or loo. treats do not need to be sweets, special stickers, pieces of a new jigsaw puzzle or reading a new library book together are great treats for a small child. IMO the toilet is the place to train to, potties are good if your loo is a long way away from the play area, but these lead to having to train twice, once to the potty and again to the loo, confusing the child. if possible forgo the kiddy seat, this will make it easier when you are out.
night training can take longer than day training, get into a routine of no drinks for a good hour before bed before trying to night train, once in this routine, you will notice dry nappies the following mornings, when this is a regular occurance then they are ready to night train, leave off the nappy, lift the child onto the loo just before you go to bed, you do not have to wake them to do this, hold them till they pee then return to their bed.