1.13. And how can I max HP and MP?
Equip a HP Plus or MP Plus Materia. Or, if you mean to max your natural HP/MP, then you will need to reset your game alot of times. Best is to take a look at the Party Mechanics Appendix, or my FAQ's section devoted to it. You need to be below the following levels to be safe for the maxing process:
Cloud Max Safety Lvl: 77 (HP), 62 (MP), 62 (Both)
Barret Max Safety Lvl: 77 (HP), 51 (MP), 51 (Both)
Tifa Max Safety Lvl: 77 (HP), 51 (MP), 51 (Both)
Aeris Max Safety Lvl: 78 (HP), 50 (MP), 50 (Both)
Red XIII Max Safety Lvl: 60 (HP), 43 (MP), 43 (Both)
Yuffie Max Safety Lvl: 78 (HP), 51 (MP), 51 (Both)
Cait Sith Max Safety Lvl: 72 (HP), 51 (MP), 51 (Both)
Vincent Max Safety Lvl: 39 (HP), 69 (MP), 39 (Both)
Cid Max Safety Lvl: 45 (HP), 51 (MP), 45 (Both)
1.21 + 1.22. How can I get Elixirs for the Magic Pots?
Yeah, you can not hurt Magic Pots without feeding them an Elixir first, so you'll need alot if you want to train there. You could just abuse the W-item trick. This requires you to have the W-item materia (gotten at the end of the winding tunnel during the Midgar Raid at the end of Disc 2, or you can dig it up at Bone Village if you missed it. Dig at the 'X' marked in the sand, otherwise known as 'Spot 4' on the picture map; www.shillatime.org/bonevillage0000.jpg
When you have the W-item materia, select the item you want to duplicate and press circle and use it. Then go to any other usable item, say potion, and press circle once, but don't use it, and press X instead. Now press circle, x, circle, x, and you'll keep duplicating the first item (Elixir in this case).
If you don't feel like 'cheating', you can also steal Elixirs from Master Tonberries and Gighees who also appear in the same area as the Magic Pots.
1.3. Can I, and how do I exit the Crater?
Yes, you can exit the crater, and it's pretty easy, too. Just don't go past the point of no return, which is when the team meets up at the bottom when you also receive items, and you're given the choice to 'let's mosey'. Backtrack through the crater, climbing rocks whenever you need to. When you get to the first screen of the crater where you've gotten the Save Crystal from a treasure chest, just go in the opening that looks like a cave. From there, just walk up all the way to the Highwind and continue your unfinished adventures.
1.4. Ruby WEAPON doesn't appear. What's wrong?
Here's what makes Ruby WEAPON appear in the Gold Saucer Desert on the World Map: First of all, defeat Ultimate WEAPON. This can be done after you have defeated Diamond WEAPON at the near end of Disc 2. Once you've defeated Ultimate WEAPON, go fight one random battle, and enter a town or something. Go back to the World Map and fly to the Gold Saucer Desert. Ruby WEAPON should show up, and it looks like a little red 'dude' walking around the desert. Don't be fooled, it can eradicate you if you're not prepared.
Trying to get 1 woman will get you nothing, trying to get 10 women will get you 10.