How I can manage my voltage and current requirement for my loads
What type of battery is this? It may be the case that the battery voltage cannot be substantially higher than 25.9V. For example, 7 LiPo cells at 3.7V would be 25.9V and the voltage is limited to that value, it cannot be arbitrarily increased. If this is the case and your sensors can tolerate 30V you don't have a problem with voltage.
You can use the DC power supply for both the encoder and microcontroller.
You have enough current header to meet the demands of the various pieces of kit but will probably have an issue on motor startup when a higher initial current is required. This may make your system &quot;brown out&quot;.
You need to look into the startup current spec for your motors.