John, using a larger ESC should not be a problem. 30%-50% higher capacity is often suggested as there is much less chance of overloading the ESC and damaging it plus it should run cooler under its reduced demand. In practice using the next size ESC up from the recommendation is common.
The only issues are the slight increased weight and possible plug incompatibility. If you have to buy new plugs and solder them you might consider applying the money to a new ESC closer to the recommended size and with compatible plugs. Save the 30A ESC for another plane. I'm a fan of Heads Up RC but there are other vendors.
Can't really comment on the servos but don't see a problem on these size planes.