It is usually better to get the more powerful motor and with highest voltage (36V)
One 36V LiFePo battery is the way to go, less weight and longer lasting, 100Ah is usually plenty
Integrating LiFePo in boats existing charging system can become complicated, if on a trailer just recharge at home
a longer shaft is better than a too short one who lifts out of the water by wave action
for SpotLock only, the battery size can be lower than using it also for trolling
for trolling purposes, interfacing the TM with the chartplotter is very useful that TM follows a route
for SpotLock only the remote control is in most cases enough
Choose the brand after what brand electronics you have already to integrate the TM on the MFD
Minn Kota Riptide QUEST has AutoDeploy/Store feature what comes handy if alone and/or frequently changing spot, but some reported that this feature did not lasted long.
Garmin Electronics --> Garmin Kraken
Humminbird Electronics -- Minn Kota
Chris