The typical canned answer is 'brew the brown ale'. The reality is among those 3 it won't matter much.
Good beer requires 5 things:
1-pitch enough yeast/proper pitching rate (you'll have that if you have dry yeast)
2-maintain proper fermentation temps - biggest mistake of most new brewers, can't be emphasized enough!!!!!!!!! Without knowing the details all of these would do well at 65-69 degrees.
3-sanitation, few things suck worse than pouring 6 weeks of work down a drain
4-good ingredients
5-PATIENCE! Leave it alone, let the yeast work. Don't worry with a secondary with these brews pitch the yeast, watch the ferm temps for 7-10 days then don't look at it for another 3 weeks. Using a secondary is NOT a problem here either.
That's my 'canned' new brewer advice.
In theory, answering your question, an APA's bitterness and hop flavors will help hide your flaws, the roastiness of a brown will help do the same. As for the IRA it's the appropriate liquid yeast that provides much of the flavor and I'm guessing you don't have the liq. yeast option. Thus in a sense the IRA will be a nice beer but won't have that true 'Irish' character of commercial examples so if that's what you're hoping for perhaps it's expendable however it's probably the kit most likely to show through rookie mistakes.
So .... go with the brown!
Good luck, have fun, don't fret too much, pay attention to sanitation and ferm temps and you'll be successful.
