If I joined a FC party to leech, so long as I don't die, you're not naked, and the xp doesn't stop- then I wouldn't care. Since FC parties are done in Abyssea, atma is going to pretty much trump any gear you have- so yes, full af3+1 would be fine to the extent that it wouldn't not work (not a typo).
More than anything, your uncertainly hurts you the most. I understand the need to ask questions, but it sounds like you've never even cleaved mobs within your own group. First and foremost, you should be running out to Abyssea and doing a test run because aside from death, watching people ***** around trying to figure out what to do would lead me to demand my money back and leave.
As a side note, if you're trying to run a FC party, but are unable to obtain +2 items, then I would question your ability to successfully cleave. Typically the support needed to run a cleave group that I mentioned earlier should be more than capable to take down many of the NMs that drop +2 items. Those roles of healer/puller are (almost) never random people you bring in through shouting and if they are, you'll almost certainly need to pay them.
Edited, Feb 10th 2013 5:11pm by xypin