spicyayam
I, or I should say my wife does my visa, so I don't have enough experience with agents to recommend someone. Because getting around Bali can sometimes be a bit of a nightmare, I would suggest looking for one that has an office in the area you plan on living in. My other suggestions would be to choose a company that has been in business for a long period of time and has a physical office, not someone who runs their business off the back of a bike.Insurance has been discussed here numerous times. Unfortunately there is never any great conclusion. Maybe get travel insurance for the first few months then decide on something more permanent.
Markit
Welcome to Bali and prepare to enjoy! You don't say where you are coming from but then your profile says even less. At your ages you will struggle to get a reasonable health insurance and frankly I haven't had one for 10 year although the wife canes me almost daily about it. I reckon it's better to save the USD $600/month to pay for crawling back onto a plane in case of anything dire and going home to have it seen to. Fact is I wouldn't let these jokers here do anything to me if it was serious anyway and the small stuff you can pay for as and when it happens. But that's me.