>today I shall remind them
For actual advice,
There’s a big 1.5 anni basically-catch up campaign going on. It lasts for about 20 more days. You should do all of those things for a ton of free wyrmite and prints and stuff. High priority, so the following HMS and Volk paragraphs are related to it.
It will give you a free anti-High Midgardsormr print and a free Flash of Genius, which just so happens to be Marth’s (old) preferred WP setup for the fight. That will let you jump right in to High Mids, which is fine as a starting point into “endgame” content. For Volk, use whatever good WP you have with Flash and find a good room with a healer. It may take you a few tries to get the hang of the fight, that’s OK.
Note that Marth is not the easiest character to get in to either fight with. Use Arctos, or Cerberus if he’s max unbound.
For your specific questions,
Weapon types come down to preference; however, each weapon type has a specific coability -a teamwide buff- and these are more or less useful. Staffs will boos heal amount, axe and spear have defensive coabs, and the others have some form of offensive boost with varying levels of niche-ness. The best coabilities are usually regarded as Blades’ and Wands’ attack and skill damage boost, respectively. They have been making a lot more adventurers with nonstandard coabilites recently, though.
It’s been subtle, but adventurer stats haven’t been a real factor for a while now. The latest few sets of new weapons have been a pretty big leap in powercreep, so you really just need to have the highest tier of weapon you can get.
Ezelith (with mana spiral)
Prince (with mana spiral)
Nef (with mana spiral)
Stay away from Lily, Lea, Ranzal, Sylas, and Zardin until their mana spirals.
Arctos, Cerb, Siren, and Cupid are good.
Kamuy is weird, just put him on one of your AI-controlled characters.
Mini Mids and Zod work on any character regardless of element, so use them if you don’t have enough dragons. Dragon buffs are interesting, but usually the most % power you can get is the best. Skill damage dragons for characters who focus on skill damage (most of them), HP or split stats for healers, can’t go wrong with strength for everyone else. Marth, for example, likes to crit, so Arctos is good for him.
Try and get to Void Battles as soon as you can, as @Qzilla8425 said. That is the easy path to good weapons, easy co-op, and specific anti-bossfight weapons. We currently have Chimera weapons for fire and shadow, those are extremely good for how easy the chimeras are.