Observing purdah with non-mahrams

Q: A family member who lives seperately sleeps on my bed sometimes (her husband returns home late at night due to working overtime or night shifts and she is afraid to be home alone at night) my brother who is 15 years and I share the same room, we have our seperated beds. She doesn't observe purdah with my brother even though he is a ghair mahram to her. My question is, will I be sinful for allowing her in my room while my brother is there?

Using freelancer.com website

Q: There is a website called freelancer.com , where a person can hire graphics designers, website designers and the like, to do work for him. One option available is called a contest, where one posts ones requirements and the price he will pay, the money is charged by the website, then various graphics designers who want to offer their services (optionally) create mock ups / designs which the person can then choose between. Sometimes over 50 different designs are made. The person then chooses the one he likes the most. The website transfers the money to that designer, together with taking a small percentage fee for using their platform. The one designer who's design was chosen, will be paid. The remainder who's designs weren't chosen, and had voluntarily posted designs in the hope of winning the contest, get paid nothing. Is this type of contest / ijaarah permissible?

Performing qadha of missed salaah

Q: I want to ask a couple of questions regarding qadha prayers.

1. What should be my niyaah when praying qadha namaz and what time of the day should I offer it?

2. How should I offer my qadha prayers, given that I have the following ones left? (I have only made an estimation, because I don't remember the count exactly): Fajr-4, Zuhr-6, Maghrib-1, Isha-Salaat-ul-witr of 2-2.5 years (around 800)

3. Do I need to offer all of the witr prayers or is there any alternative to it? I request you to outline the complete method, so that I can offer them as quickly as possible.