So I wasn't too keen on the calculations done earlier in this thread regarding the ABV after the limeade is added. It seems like only the extra sugar was considered, not the increase in volume. One bottle of limeade is 1.75L, or 0.462 gal, and contains 28g sugar per 8 oz. This means there is ~207g of sugar in a full bottle. Once this is converted (assuming 100% yield), you end up with 111g of ethanol, or 88mL. 88mL/1750mL is 5.02% ethanol from just fermenting the limeade.
Now let's look at the rest of the beer. I put the grain bill into Brewer's Friend with 80% efficiency high attenuation (77%) to allow the highest possible ABV. I also used a final volume of 5.538 gallons (6 gallons - limeade volume). This gave an OG of 1.061, FG of 1.014, and ABV ~6.18%, nowhere near some people's ABV in the 7-8% range. If you add up the total acohol in each and divide by the new volume, it will lower the ABV.
5.538 gallons * 0.0618 = 0.3422 gallons ethanol from the beer
0.462 gallons * 0.0502 = 0.0232 gallons of ethanol from the limeade
(0.0232 gallons + 0.3422 gallons) / 6 gallons = 6.09%
.46
Unless something weird goes on with the beer or limeade that I don't know about, it should slightly lower the ABV, but a really insignifcant change. Also, I am going to measure the OG of limeade and ferment it, for science. I will get back with the results.