I feel very clueless

my puppy is around 4-5 months old and is a terrier (best guess is a smooth fox terrier) but he is definitely a mix of some kind.

I want to get to the point where he can be completely freeroam and have the downstairs for himself to roam, ive puppy proofed it and am going to put a puppy gate on the stairs (this means hed get the whole living and kitchen area), hes currently crated in our bedroom when we arent home or when he needs a rest but he keeps toiletting in the crate so my best thought is to remove the crate entirely and restart the toilet training process.

I do still think it would be safest to use the crate overnight though as we have 4 other animals (3 cats and a chihuahua) and he is quite boisterous and always excited by them but im just really not sure what to do and i also feel like even if i think ive puppy proofed downstairs im worried hes gonna somehow find Something.