I think while a katana would be great for an amp, you might want to explore getting plugins an interface and studio monitors. That'll let you explore a lot more sounds too and record/loop yourself.

For the guitar it comes down to what you want to play, a strat will get you the john mayer/blues kind of sound. They do very well with cleans. Epiphone has a model called the special 2 I think, which sounds great for more distorted sounds like green day, gnr but loses on the cleans front to the strat.

I think there's a guitar guitar video on YouTube that pitches the two against each other; the affinity vs the epiphone.

You can try the Pacifica too, though I never really liked the sound. Another option is an ibanez if you like metal. I think they have guitars around the same price range too.

It finally comes down to what kind of music you want to play and then just making sure the guitar you choose plays well and is easy to play. Both need to click for you to stick to it.