Btw since I haven't really played MH before, what are the restrictions on changing weapons? Is it just a matter of having the materials to craft a decent tier weapon of another type, or is there some sort of skill specific to weapons so you'd have to go back and hunt some early shit to use a new weapon? A bunch of these weapons look cool to me so I'd like to try various playstyles, just wondering if I can just switch freely.
You can try any weapon whenever you want, given that you've crafted it, but it is not on the fly swapping mid combat or anything. The only restriction is that you cannot change your weapon or armor away from town or possibly the hunting camp now in MHW. The hunting camp which can just be considered the standard starting location for any biome.
There should be a free "newbie" weapon for all 13 weapons. If this is your first monster hunter game, you should seriously try them all out. Find your style, its part of the elegance of Monster Hunter. There are weapons with extremely complicated move trees, and others that are simple by comparison. Your save file is a giant canvas that you can hunt and fill with whatever armor and weapons you want to harvest the mats for. The bottle neck to upgrading multiple weapons simultaneously is that they may require parts from completely unrelated hunts, or they can share a rare drop or 3. There is a "money" cost to upgrading, but that will not be your limiter unless your goal is to "try and make everything". Trying out different weapon types is most rewarding at the start of your save file.
Weapon crafting is so complicated that describing it is dumb. In light of that here is a link to the resource that all monster hunters previous to world have required referencing to min max planning. Some are not that great, some are elemental, some are status, many are precursor weapons. Some are sharper than others (this interacts will monster defense values on a body part basis to determine damage per hit and move). There is a giant chain of beasts that are necessary to hunt to traverse any weapon from its first to final forms. The weapon crafting imformation contained in the next link, appears to all be in game at the smith (a fucking amazing change). Hopefully armor gets the same treatment.
This is only one weapon, the longsword, this shows every single weapon stage and its name in the game.
Long Sword - MH4U - Kiranico - Monster Hunter 4 Ultimate Database
Here is the information chart for the simple monster, the dragon, Rathalos. Also from the same database.
Rathalos - MH4U - Kiranico - Monster Hunter 4 Ultimate Database
Things to notice, are the resistance levels by body part to different damage types, including physical. The status vulnerabilites follow, and as you descend the page you'll see all possible drops, their percentage chance, quests the monster is part of as well as all the weapons and armor Rathalos drops create. The percentages of Rathalos damage zones are all quite friendly to all 13 weapons, but some monsters aren't so universally (mostly) vulnerable to all weapons. Although for example, a fire elemental weapons fire damage component will be almost entirely resisted, while dragon or thunder are 1 and 2 for elemental types. Extreme resistance or vulnerability are not features of early game monsters.
The core of the game really is about learning the monster movements/tells, and then wielding whatever weapon to maximize damage to the monster and minimize it to the player. As difficulty goes up, the speed of the monsters, movesets, and the durations and combinations of tells all get more complicated. A lot of the variety comes from the environment. Players can dominate with any of the 13 weapons, but some of them have few true masters. One other thing to remember is the game contains a load of items that are universal to all the weapons, traps, bombs, potions etc.
Longer than I intended, I love me some monster hunter.