New owners who could use a little help.

Hi everyone, I'm new to the site and i guess owning a cat in general, and could use some advice. Sorry in advance for the lengthy post, as  a new owner I would prefer to be thorough and learn what I can. Recently my family has added a new kitten to the house (which my mother named Porsche), and I could really use some tips. Here's a little breakdown of the situation:

The new kitten we recently adopted was a stray found with her mother and a brother and sister. The person we adopted her from said she was about 2 weeks when found and she was about 7-8 weeks when we adopted her. Since we brought her home, she has been kept in a small bathroom that we don't really use, with a little house to go in, a mat/bed to lay on, many toys, a litter box and her food and water. We  have another cat in the house, a 2 year old male (my brother's cat which he moved back home with when he was already a little older than a year), who is very playful and friendly with us but extremely skittish to anything new (people, animals, objects, sounds). Because of this we have a medium sized cage in my bedroom that we keep the kitten in during the night to give the 2 cats exposure to each other. 

We have had this new kitten for 1 week, and since then she has not seemed to warm up to us at all, although she seems very anxious to get out and play with our older male, Biscuit. When in the cage, she watches us move about and remains very calm and plays with her toys. When alone, freely moving around the bathroom she is the same, quite playful. However, if we move towards her and reach out to her at all she cowers away. Either running into her little house, or running into a far corner to stay away. My mother has been told by friends that we have to hold her and pet her to get her use to the contact with people, but she doesn't seem to be taking to it well, she is calm for a bit if we pick her up and pet her but always struggles to get free and away. However I've now read in a few places that forcing contact on her could make it worse so I try not to make contact with her unless i need to move her to another room, in which case i hold her for a few minutes and pet her. Also our older male cat seems like he wants to keep his distance (he doesn't seem aggressive, more curious then anything, he just sort of watches from a distance even while she cries out and reaches through the cage for him), so we have not let her freely roam around the house fearing the first interaction could go badly. My stepdad also said while holding her the other day she hissed and scratched him so he thinks she may be feral. He has been the only one that she has done that too, so I'm thinking it may have been something he did.  

That's basically where we are at this point, based on how we have handled her so far, what could anyone tell me? What we are doing wrong, what you recommend, ect. Any input would be extremely helpful, thank you. 

I've dealt with a lot of ferals and strays when I worked at an animal shelter and the best way I was able to make them sociable was to start slow, if I wanted to pet them, I always used a toy to do so, as if it was an extension of your fingers so they wouldn't feel threatened by a hand coming at them. I know it's tough but it did take a week of this for them to accept that I wasn't a threat, but after that I switched to my hand and scratched their head and ears to see where or if any place was too sensitive to touch and then went down their back. let me tell you though, every single one I helped rehab got adopted cause they became the most people friendly cats in the joint lol. it just takes time and patience

I'm trying to get some ferals used to being petted at the moment, so that when the time comes for them to be spayed it will be easier to get them into cat carriers and to the vet. (I'm more of a cat whisperer than a cat trapper, I've realised.)

This is what I've tried;

Kneel down on the floor near the kitten with some cat treats or a toy. Wait until she is eating or playing then gently smooth the back of your hand along her back, near the base of her tail to start with. If she sees your hand coming she'll try to run away but if she is focused on something else she'll tolerate it for a few moments before she thinks, "Hey, what's that on my back?"

Take your hand away or let her move away when she notices, then when she is focused on the food/toy touch her again.

I think once she gets used to having your smell on her she'll be easier to touch. The key is to go slowly and don't rush things.

Hope this helps.