axle breather mod questions

ok my breather is toast, the cap is crushed and bent, most likely because it appears the previous owner replaced the rear axle from a salvage yard because I see it has yellow numbers written on the housing.

I have to replace my breather so I was looking at the relocation mods but since I have a stock height regular 2wd, im not going to be running the hose way up inside the bed or to the fuel door as others do but rather I will just pin it up on top of the frame rail or to the underside of bed for added ground clearance to keep it clean and dry like on most 2wd trucks. I tow a boat so while I don't expect the axle going underwater you never know when it might get wet because shit happens at boat launches lol.

anywho here are my questions:

what is best type of breather - is it better to have a free flowing filter to allow air to go in or out as it wants, or is it better to have a factory breather cap that is a check valve and only lets air out and could, under the right conditions, form a vacuum in the housing?

which filter to use - assuming a free flowing regular filter is better should I use a paper element type air filter? or fuel filter? or one of those small metal screen filters used for lawn mowers? which is the best option and why?

fitting size - I see threads mention the breather is a british thread design and that is why you need to use a Toyota or Nissan fitting so the threads match but some threads say its 1/4" npt and give you a regular brass nipple to use so are they using the wrong fitting but the soft brass rethreads itself to the harder steel threads in the housing? what is the correct fitting to use because I do not just want something that you can make work?

hose clamps - lastly some kits have hose clamps and some don't but why? I realize there is little to no pressures involved to blow the hose off but shouldn't you always have a clamp on any hose connection?