Is a white wetsuit re-stocked? If yes, I'd like to buy one 
Also, about your DS glitch... Of course I don't know your situation, but.. I think I might have an idea why that happens. (Unwanted advice incoming, apologies) Basically, if you open your gate before the Mii of the newly added friend appears, that's when the other person can not see when your gate is open. That's actually pretty logical, because a Mii only shows up when both parties have added each other as friend. So, according to your DS, you guys are not friends yet, thus can not visit each other. What I do to prevent this is keeping the friend list window open until it updates and the Mii appears. After that I open.
Also, about your DS glitch... Of course I don't know your situation, but.. I think I might have an idea why that happens. (Unwanted advice incoming, apologies) Basically, if you open your gate before the Mii of the newly added friend appears, that's when the other person can not see when your gate is open. That's actually pretty logical, because a Mii only shows up when both parties have added each other as friend. So, according to your DS, you guys are not friends yet, thus can not visit each other. What I do to prevent this is keeping the friend list window open until it updates and the Mii appears. After that I open.