Battery Options?

Guys, would appreciate your input on some battery-related questions I have ...

First here's what I need to power with the choice of battery(s):

I've got a Fin and Feather (LT25-like) I'm outfitting. I plan on having an electric start 25hp motor with an external tilt&trim unit. 43lb Great White trolling motor. Have bilge pump, bait pump, lights and fishfinder I'll want to get juice to ..... I don't have any specs on any of these devices in terms of amps needed, etc ....

I'm pretty sure I'll get an Optima battery or other AGM type. That said, .......

1) Any reason I can't have one dual-purpose battery to run everything? If so, what size might you recommend?

2) If you think I should have separate cranking and deep-cycle batteries, why and again what sizes might you recommend given what I told you above about my setup.

Really appreciate any comments as all this stuff is new to me ....


AP