Thank you for your question. I will do my best to try to answer your concerns. There is a bit of a language barrier, so if you don't understand something, or I don't fully answer a question you were asking, please reply and let me know, and I'll try to explain further.
In answer to your questions:
1) No. Police need what is called probable cause
to search someone. For example, if you get stopped for speeding, and you have drugs sitting on the front seat next to you in plain sight, that would give an officer probable cause to search your vehicle.
2) That's a very broad question, so I don't know in what circumstance you are asking, but generally, yes. For example, let's say the police get a tip from that there are drugs hidden in the attic of the home where you are staying -a house that is known for dealing drugs and a lot of drug activity. They can request a search warrant for the home to search for the drugs.
3) With probable cause (a reasonable belief that a crime was committed) yes. They can arrest them at home, work, while they are out, etc. Time of day doesn't matter, either.
4) I'm not sure what you're asking here. Are you asking if it's right that you were made to put on a jail uniform at the jail, yes, that is typical of most jails that people arrested are made to wear jail clothing.
5) Bail is never guaranteed and is left to the judge. There can be many reasons a person is denied bail -for example, for serious crimes like murder, if a person is on probabtion or parole when arrested, if they are a repeat offender, or if they are believed to be a flight risk are just some of the reasons a person may be denied bail.
6) It really doesn't matter where you are from - except that if a judge believes that you might try to flee the country to avoid prosecution, they will take that into consideration when deiciding bond.
7) All persons who are detained at the jail are stripped search (normally when they are made to change into jail uniforms). If you're asking why yours took longer than other people at the jail, I can't say - I wasn't there, but racism may have nothing to do with it. The guard doing the search may have been new and inexperienced, they may just be slower than others, they may be more thorough in their search than other guards.
8) Yes they can. It is common for people in jail and prisons to smuggle contraband such as drugs, and sometimes even small weapons, in their buttocks, so it is standard procedure to check a person's rectum.
9) That is up to the jail itself to set that policy, but there can be yes. A jail may dress its most dangerous inmates (those accused of murder, for example) in different colors for easy identification.
10) Yes, if you believe you were treated unfairly or differently than other persons at the jail.
11) Yes, the record is still there. You would need to see a criminal lawyer in your area about having the record sealed or expunged, meaning the records couldn't be seen in a background check if they were sealed or expunged. Documents have to be filed with the court in order to do this, and the process can take months to finish due to the high volume of cases judges have. A lawyer would probably charge around $1,000 to expunge an arrest record.