goingtobefree, sorry that you are having a stressful time at the moment! It's easy to book fastpasses via your My Disney Experience account but you need to have tickets before you can do it. Once you've got them go to 'My Reservations and Tickets' and then you'll see a button saying 'link tickets'. From there the website explains what to do. Choosing your times is a little more complicated though - it chooses the times for you and offers you 3 options, most of which aren't usually exactkly what you want. So just choose the time closest to what you want and then you can alter each ride individually. NO idea why they do it this way - would be so much easier if you could just select individual times yourself at the time of booking!
I'm not sure about character breakfasts as I've only done one (O'hana, which was geat but pricey) but it's easy to meet characters. On the day you arrive at the park there will be a separate leaflet that lists the times and locaitons of all the characters there that day. Be warned that if you want to meet Anna & Elsa you are in for a VERY long wait (speaking from bitter experience - 4 hours!!!) You can FP a meet with them now but you have to get in quick, as soon as your 30 day window opens.
DogHairs, I can never decide when to book my FPs! There are lots of strategies. I think Bacon's one of arriving at rope drop and booking FPs for later in the morning is a great one. Once you've used your 3 FPs you can book further single ones, so booking original ones for 11am-ish means that you'll have plenty of time to book more for the afternoon (whereas if you've booked for 4pm-ish, you prob won't be able to get any more for that day). What rides are you booking for? If you have rides that you know are near each other then I suppose it makes sense to book them in s short time space - but there are shortcuts around the park so I don't think it's a huge problem to zig zag about a bit. Remember that you get an hour's timeslot so if you're in one land and do your 1st FP at the start of your timeslot you'll probably be waiting around a bit before your 2nd timeslot opens up.
Oh this is LOVELY. I've had a crappy week with both DCs off sick and this is the first day they've both gone back to school and I can come and talk about my happy place :)