All kittens are individuals. It is not uncommon for a 5 week old kitten not to be interested in solid foods yet. I start introducing solids at around 4 weeks old, but they are still getting most of their food from nursing Mom. Just keep offering it a few times a day, and eventually she will figure it out. I had a litter that refused to eat solids until 8 weeks old. Very uncommon, but they just refused, and they had good weight on, so I let them take their time.
I would recommend continuing to warm up the mush and KMR. You might try a rubber tipped baby spoon or a syringe to feed her a couple of times so that she is trying it, but I wouldn't force it.
I have never had an orphan, but I would think feeding the bottle still would be fine, as long as she still is accepting it. A syringe at this age may be easier to feed with. There may be others that have a better opinion on continuing bottle feeding.
Please feel free to rant, I know it can be frustrating when you can read certain websites and it say one thing, but no matter how hard you try, the kitten refuses to be "textbook".
While all the websites and advice is helpful, it does just come down to the kitten still not being quite ready for solids yet, but she is doing great. I can tell by the new picture of her. She will surpise you soon, by reaching another miracle milestone, when she does decide to begin weaning.
We will all be here to cheer you and Azriel on, when that time comes.
You are doing a great job, Meowmy!!