RE: Questions about electric planes
1. I try and use dual conversion receivers every time. Just seem to be less suseptible to interference. Especially in city areas where things get a bit busy. A lot of the time a single conversion receiver will work fine though.
2. Most LiPo's these days have two seperate connectors. One is the connector that hooks up to the ESC and in some cases is used for charging, it is the fat red and black wires. The other connector has a much smaller plug with 4-6 small wires or so depending on the cells of the battery and the manufacturer. That connector is for balancing, or in some cases charging depending on the charger you are using.
3. It is highly recommended that you use a balancer, it just keeps the cells in check and helps you maintain your battery and extend it's life. Again, it depends on the charger you use. Some are balancers/chargers in one.
4. The HS-55's are a perfect match for that plane.
The charger that seems to be a good bang for the buck is the Cellpro 4S from FMA. It balances while charging, and is $55-59 depending on where you get it from.