Wow, that's a pretty impressive track record!
Is the Loss mode in Elona the one with permadeath? If so, you're a madman. I enjoyed Elona for a while, but could never bring myself to try it with permadeath.
Do monsters pursue you if you go up or down levels? The way that monsters pursued me in games like Brogue when you went up the stairs often led to some pretty cheap deaths there.
To specify, they will follow you if they are near you while you go up the stairs, like in NetHack, but won't follow after you later like in Brogue.
Which pieces of weapons and armor should I look for in the early game? I heard that large swords like longswords and arcanite alloys for armor are the best option. Or should I look for something else?
Equipment in IVAN is often about trade-offs. Plate mail offers exceptional Armor Value, but penalizes your Dex and Agi. Chain mail is the middle ground, while cloth/leather armor gives less AV, but with no stat penalties. Similarly heavy weapons will be more damaging but less accurate, and light weapon will do less damage, but strike much more often.
Dual wielding is strong, as it gives you two attacks and two block chances. Two-handed weapons, on the other hand, have much higher damage. I personally also think that shields are quite viable nowadays, as they give you a boost in AV and
a high block chance.
Should I train my character in any way before doing the underwater tunnels? I heard that a tactic called banana kicking is not a valid training option.
You should be fine with no exploits or grinding.
If you find any bottle of can with ommel stuff inside, drink it for sweet stat boosts.
Is there a way to export your character’s stats in a readable format for other players to consult like you can in Dungeon Crawl: Stone Soup or Angband?
Sorry, not yet. It's been sitting in my TODO list for a long time...
Any other tips are appreciated!
Unlike in other roguelikes, you total HP is not that important to keep track of. You can have your head cut off while your HP are still high if only your head is damaged. Have a look at the body part mannequin in upper right for color changes: bright red means the limb is dangerously damaged, striped grey means it's likely to be destroyed if you don't do something about it right now.
It's good to have either fire resistance, searching or levitation as you go to the Gloomy Cave.
Golems are often more dangerous than they look, but they tend to be slow and cannot see invisible.
Explosions and some monster attacks can break wands, and wand explode with their corresponding effect when broken. It's better to have all but your emergency wands stashed in a small chest, as a cascade of exploding wands can cause a sudden YASD.
Have a look through the starting village and later Attnam, you might find some useful NPCs.