The only thing I can say on the matter is that almost anything and everything can essentially be 2-3 manned now. I won't lie, starting off is always rough but you have to want something enough to merit attaining it. We received help from our dear neighborhood fat to give us a leg up, but after that we've been doing everything essentially by ourselves.
Mind you, we've grown in size since we started. But I can attest that things from simple seal NMS to full stage empyrean weapons can be either solo'd or done in a group of 2-3. It might be a bit harsh to say but, the only thing stopping you from getting nice ***is your ( not aimed at anyone just using it as a general phrase) laziness and either ineptitude to get things done.
Also as a protip: Never really fully believe anything the wiki says on a mob in terms of difficulty, it's usually people who blow things way out of proportion.