I have a question. im making a mod and the models are only on some of the characters and the rest are just normal soldiers

Some expansion on what you did might be nice - as far as I know, some soldier models you added aren't always appearing. How did you add these soldier models? Did you replace any lines of code, etc?

yes
and i deleted the other regular soldier models and replace them with mine

It depends on how many you replaced. Each faction has three soldier variations, so if you only made one new soldier and replaced one variation, then you will still see the two vanilla variations running around.

i had 2 so should i make 1 more of the same model or just make a new one

You can do either - both will result in the faction no longer using the vanilla models.

You can also modify the faction's .xml file under the "factions" folder - however, if you're overwriting vanilla files with the soldier models, I don't suggest you do this one.

i also tried(this is for the guns) adding more than 1 gun(made costom gun) did the exact same code and everything(evept model and name) but it wont show up in game

It's more complicated. You have to make a .weapon file for it (copy an existing one, preferably close in design to the one that you want to make and modify it to you liking, not forgetting to change the key name) add it to a "<faction name here>_primaries.xml" file as well as the all_weapons.xml file. Also, make sure it's got a high enough commonness value so it does show up, if you want it to be like that.