1. Ant-Man, Wasp, Hulk, Iron Man, Thor (#1)
2. Kang, Rama-Tut, Scarlet Centurion, Immortus (#8)
3. Dr. Doom (also #8)
4. Captain America (hm, but when was it? I know they tried a bunch of variations before settling on this one. was it on the cover of #16 before they got it right?) [edit: added this in because I did not see the question originally]
5. Because the Avengers just invited him to join the team even though he had tried to kill them. (#58)
6. The Super-Skrull (around #92)
7. It was the Collector, right? (#120) [edit: removed some text because the tagging crossing it out had failed]
8. Libra (#123)
9. This is tricky, as Black Widow and Hercules both hung around a long time before joining. I'm not actually sure which issue Herclues joined in, but I'm guessing:
Captain America (#4)
The Black Knight (#71)
The Black Widow (didn't officially join until #111, though she left the team in the same story)
[edit: did Widow join in #45 like some of the others are posting? I don't remember that, for some reason I thought it was a situation where they were going to make her a member but she left on a SHIELD mission or something before they could make it official. I'll have to re-read that issue! I'll stick with #111 as my official answer, of course]
1. Silver Surfer, Hulk, Valkryie, Dr. Strange, Namor and Hawkeye (#116-118)
2. I don't think I know this one! Not that familiar with NYC. J.P. Morgan's home?
3. Dang, I can't remember it. I'm going to kick myself over this one. Arrgh!
4. Tough question! Let's see, how about Spider-Man (in ASM Annual #3), Daredevil (in Avengers #111) and Captain Marvel (during his crossover around Avengers #125 I think)? Boy, I am second guessing myself here. They may have invited Dr. Strange to join in #61 since they only had like three active members in that issue.
5. Captain America, Vision, Black Panther, Hawkeye, Black Widow, Iron Man, Thor (7). The Fantastic Four (4). The original X-men and Professor X (6). Dr. Strange, Daredevil, Spider-Man and Nick Fury (4). = 21 (#60)
1. At the beginning? I know they trapped him inside a radiation proof vault at the end, because radiation = magic for some reason. But at the beginning? Was he on an asteroid or something? I don't remember.
2. Hmm. One of them is Hercules, though since this is before he appeared in Journey Into Mystery, he didn't look the same and had no beard. One is Merlin. I think Genghis Khan. And the other two… I'm not sure. Napoleon and Julius Caesar? (#10)
3. I am going to kick myself for this one, I used to know it. [edit: I looked it up because it was driving me nuts and sure enough, I can't believe I forgot this one] (#93)
4. See above. Arrrrgh.
5. The original Human Torch, the Patriot, the Fin, the original Vision, Blazing Skull, Namor, Captain America and the Whizzer? I bet I only got like 6 of those right. (#97)
6. Alfred Lord Tennyson? Man, I know the poem is about Ozymandius. But who wrote it? My English professors would weep in shame if they saw this. Keats, Jonson, Coleridge, Shelley… oy vey. How embarrassing (#58)
7. No idea! But it must have happened in #76 (or… hmm, I haven't read #84 in a long time). I'll just guess Shakespeare, because, why not.
8. The Evil Eye of Avalon? (#116-118)
1. good lord! Who the hell is the beast brood!? Are those the guys that were hanging around with Magneto in the savage land in #105? Magneto, Lorelei, The Toad… I don't know. Were the Ani-Men part of the Beast Brood?
2. Baron Zemo, Frankenstein, the original Human Torch, Wonder Man… uh… Bucky? Toro? (#132 I think)
3. Man-Ape, Living Laser, Ultron, Grim Reaper and… Whirlwind? (#78-79)
4. Valkyrie (the Enchantress in disguise), Black Widow, Wasp, Scarlet Witch and… um, Sue Storm? (#83)
5. Baron Zemo, The Melter, the Black Knight, the Enchantress and the Executioner (#6-7)
6. The Melter, Whirlwind, Ultron (as the Crimson Cowl), the Living Laser, the Radioactive Man and Power Man? (#54-55)
7. I should get points for even knowing who you are talking about. Wow, that's obscure. I'm not even sure, but weren't these guys just bank robbers or something, maybe working for Cornelius van Lunt in #77? And they just had like really dumb gangster code names. I don't know… Gentleman Jim? Jacques? Tommy Two-Fingers? No idea. If anyone gets this, they deserve big props.
8. Dr. Spectrum, Hyperion, Speed Demon and Nighthawk. I think. (#70)
9. Titanium Man, Crimson Dynamo and… uh… The Slasher? Or something? Didn't they run into these guys in Vietnam around #130, while Steve Rogers was in his Nomad identity?
10. Thunderboot!!! Piledriver and… Bulldozer? (#39!)
The Swordsman's last words: I don't recall. Something about being a loser, probably. Englehart always had him talking about that. (Giant Size #2?)