No. There is no law or mandate that prohibits Jehovah's Witnesses from having non-witness friends. Close interactions with "worldly people" (as all non-witnesses are referred to) are severely avoided. Being friends with a non-JW is considered to be disobeying God. Since Jehovah's Witnesses believe that living and acting in accordance with their teachings brings them closer to God, the only appropriate relationship they can have with anyone who does not share their beliefs is one of friendship.
Having non-JW friends may appear to be harmless enough activity, but it can have serious consequences for a Jehovah's Witness. First of all, they might betray your trust by telling you things about themselves or their religion that aren't true. For example, a non-JW friend might tell others that Jehovah's Witnesses are evil or do bad things. This could lead someone who believes this about Jehovah's Witnesses to try and convince others to become one too. Also, non-JW friends may influence Jehovah's Witnesses by giving them ideas about other religions or cultures. For example, a non-JW friend might show a Jehovah's Witness a picture of a church building and ask them what they think about it, then go along to one service and comment on how nice it was.
Is it possible for a non-religious person to date a Jehovah's Witness? They can, of course. The key question is whether a sincere JW would want to date someone who is not religious. There are persons who profess to be JWs, and may even be baptized JWs, but are not actively involved in the JW movement. Such people may or may not believe everything that the organization believes, but they are not persecuted for not believing as the organization does. They may have friends or family members who are JWs, but they aren't forced into hiding or abuse because of their relationships with them.
In order for two people to have a successful long-term relationship, they need to understand each other's beliefs and preferences. If one partner is very open about not believing in Jehovah God or in an afterlife, and the other is active in the religion, there could be problems. The active JW might feel pressured to convert his or her non-JW partner, or at least not express any interest in doing so. A sincere JW wouldn't want to cause anyone else pain, so conversion is usually the easiest solution. However, some active JWs might not want to change their beliefs, in which case they should be accepted as they are.
It's important for partners in any relationship to get along with each other's parents and friends.
You may certainly make friends from other religions. And it may have no bearing on how you connect with them. The reason for this is because certain faiths have practices, ideals, or traditions that differ from yours. If religion is an issue, it is entirely up to the individual. They may be Muslim and you may be Christian, but that doesn't mean you can't get along.
However, sometimes these differences cause problems. When this is the case, it's best to know about them before you become friends. Maybe you will find out that one of your friends believes in doing things differently than you do. That's okay - just be aware of any potential issues that may come up later if you decide to stay friends.
Here are some examples of different religions and what they typically believe:
Christianity. Christians believe that Jesus Christ is the son of God and he died for our sins. He was raised from the dead and now lives within everyone who believes in him. Through his death and resurrection, Jesus freed us from our sinfulness and gave us new life through his grace.
Judaism. Jews believe in one true God and that Moses was a great prophet. They also believe in the Torah (the set of rules given to the people by God through Moses), including many mitzvahs (commandments).