Will be fishing in northern Indiana soon, water temp will be around 45.  Are females feeding on bluegills or big swimbaits yet? 

Welcome to BR

Bass (and all fish species) feed year round.  The question I think you wanted to ask is: Will female bass be actively feeding with water temps. in the mid 40's?  There are a lot of variables to consider and the biggest would be recent weather conditions.  IF daytime temps. have been consistently warm AND  the sun has been shining over the previous three or four days, the bass should begin moving from their winter homes. Catching will likely be better later in the day when the sun has had a chance to do it's thing, but don't expect to find numbers of fish up shallow and close to shore.  A flat sided, bluegill colored crank or swimbait may pick up some fish, but if you're fishing Webster or any of the lakes near it, a perch pattern may be a better option as they will make a move to the shallows before the bluegill do.

You throw them long enough and a bass will eat them. I caught a few on the new Savage Gear 3D bluegill here in Kansas last week with water temps around 50. 

 jerkbaits, cranks like a wiggle wart.

http://www.bassresource.com/fishing/spring_baits.html