Hey there! Firstly, when I did my application last year there was no option like you have. It was search for your own job or don’t go. This full placement thing is a new addition for Bunac so I can’t really comment on it too much. If I was to do it this time around though I would definitely choose that option.
Finding a job was very difficult. After losing my first job it was next to impossible to find a new job and very stressful. You can get lucky but even then there is no guarantee that the employer will keep your job contract in place. It’s not a nice position to be in. So I’d recommend full placement unless you really are set on a particular location.
I’d only get a second job when out there if you find that you want one. I got one because I had too much time on my hands and I thought I may as well earn some extra cash. And yes you have to inform your sponsor of your new job and get it approved.
Good luck with everything, any more questions send them my way. If you do have a particular location in mind, you can aim for this but you could also do what I did – I wanted to work in California but ended up working in not-so-familiar Wisconsin. So instead I travelled around California for 3 weeks and then settled in Wisconsin. Where I worked actually turned out to be my favourite of the places I visited. So try be more flexible if you can and it may turn out for the best.