Video editing - remove text

I have a video that has a person showing some demo, however it has texts showing on the video while it is playing. I want to be able to remove the text, let the video only showing the demonstrator. Another one that has a watermark similar to what you see the logo "Youtube" on any video, If you can remove that watermark, it will be great too. The first video i only need the first 6 minutes or so, You need to speed it up to about 3 minutes, remove the audio it had and mix a music to it. the steps: remove text/watermark split the video (only need the first 6 minutes) speed up playing speed remove audio mix a music