I honestly have a over the top first person viewmodel setup for my game and here is a breakdown of how it works. I am pretty sure it can be handy for future developers as well. You don’t have to make everything like this, it is a way of flexible approach, depending on the time effort spend you can do differently.
As said you can simplyfy depending on the needs of your game. It is also possible to render transparent materials on character if you define them on certain points. Arms Legs Torso. Eventually you will need to setup a viewmodel, better to do it yourself.
If skeletons are same you will not have any problems with animations since you asked a true FPS wanted to share, some of the tutorials on the internet are not true fps viewmodels.