I solved it.

All the time I was trying to replace sc_selcharacter_en.pac. What I did not know at the time is that, I should replace common5.pac

are the csps in the correct size?

By the correct size you mean, that the sc_charselect-en.pac should not weight more than 3,79 mb?
Yes, I suppose they are, when I extracted link CPS i replaced it with one that was even smaller in size - about 8,99 kb. It's like brawbox is corrupting those files, or something.

Pics size: 128x160 , PNG.

Allright. Firstly sorry for my English, I'm not very good at speaking. Secondly, hello  

I have a really big problem with NTSC brawl, with CSP to be accurate. When I'm trying to replace any of them, the game just freezes when i choose to Brawl.

I searched all over internet and it seemed that I had issues with file size. So i downloaded "Shadowkong" extracted CSP from it and tried to replace Link second costume with it. Well... it still freezes. I also tried to save it in other format (don't remember name now...) than C18. But notjing works.

I should also note that I'm using Wiiscruber and I tried several versions of brawlbox. I'm editing the game ISO itself, not using any riivolution stuff or anything. I tried replacing PAC and PCS files, also music files that way and it works fine, the only problem i've got is this irritaiting situation with CSP  

I would really appreciate help. I hope I wrote this clearly. It's like 02:00 p.m here xD