Yup, it's rather easy to get all the equipment slots + Max skill on a bronzie (at least, it's a lot easier than for 4*+)

So this may be a silly question, but I wanted to know for sure. Do the attack and defense battle buffs stack? If no one knows, I might just try this myself when I have extra stamina.

EDIT: I'm dumb. I just turned off fast forward and could see the buffs. It looks like they stack additively.

So i decided to have a little look at the 1-3 vs 2-1 argument because i randomly started playing on DMM as well. This naturally meant i must pick a farming map for my early levels.

After checking the average gold per map as well as seeds and the gold from selling the 2* girls i can conclude that the difference is:

1-3 costs 3 less stamina.
2-1 gives more seeds and more exp per stamina.
Both of them have about the same gold efficiency if you count in gold from both selling girls and map gold itself.

So in the end it boils down to whether the one choosing decides that he wants less seeds and exp in favour of an amazing 1-3 more runs at early levels.

If someone is concerned about seeds and exp they should be running 5-4 anyway, its easy enough to get to and gives the best seeds and exp of all the maps that lead to the 12 stamina secret garden.