First of all, let me greet everyone on this forum :3
I'm glad to be part of the community.

I've been working on game development for the last couple of months (primarily working with 3D software, modeling assets and preparing everything for import in UE). During the process i've begun to think about the animation (just thinking this process through) and stuck on couple of questions, which, i believe, are important. I'm sorry in advance for possibly stupid questions and i hope, that you'll help enlighten myself :3

1) When you need to animate a combination of characters (i mean, let's say if someone is grabbing another character, or performing a finishing move or something), am i right to think that you need to animate the whole process (with 2 characters for example) in 3d software (in my case - 3ds max) and then export in UE? And after that i'll need to trigger the combined animation via certain circumstances (doesn't really matter now). I'm asking because previously i was thinking that you need 2 separate characters imported into UE and you create a combined animation in Engine itself, but as far as i understand, it's quite a stretch

2) Very similar to the first question. When character is performing a climb (lets say climbing up the wall and his hands are clambering the corners) how do you animate this process correctly? Do i need to model a specific parts of environment (ladders, poles, corners etc), animate it's behaviour with character and only then export everything in UE for further programming? Or there's another way?

3) Soon i'll need such effect, when my character is grabbing a weapon and it's appearing in his hands (and i mean not just taking it out of his\her pockets but like it's materialising out of air). Here i understand the entire process of animating character with weapon in 3d software, but the effect of "materialising" is the thing that bothers me. Am i right to think that i can create basic animation of taking out a weapon and then, after exporting everything in UE, add an effect of materialisation to a weapon itself (not entire character)?

I'll be glad for your help and your answers :3
Thank you in advance!