How to create and export color editable vector bitmaps (for texture stamps)

Greetings,

I am an intermediate level user of illustrator, and am trying to explore creating custom texture stamps and brushes since having become familiar with some I purchased online. I have followed a few tutorials on how use image trace to create the editable black and white vector images, so i think I’m part way there, but upon exporting to PNG or TIFF they become un-editable when placing in a new file. I’m only interested in being able to change the colour fill.I feel like I am missing an important step and was hoping for assistance. I will break things down so you have an idea of what I would like, and where I am at now:

1. I would like to create  color editable bitmap file such as the one here i purchased from True Grit Texture Supply Co. The color can be change be simply one step click and color fill of your option. I see at the top it says Black & White Bitmap PPI 1198. I want to create something just like that.

   

2. Here is what I have successfully achieved. I used image trace over a photo of a tulip and then used unite and create compound path after removing white so that the file is one click color editable like above. It is still an illustrator file though.

   

    

3. I tried flattening the transparency and rasterizing the image.

   

   

    

4. I tried exporting to various formats, especially TIFF since that is the format that my original bitmap textures i purchased  were in. Its not lost on me that the original file says its “Black & white bitmap PPI 1198” vs the one i created which says its “ Transparent CMYK PPI: 310,” I just want to know how to get to the former so that i can export my textures and place them easily in new documents. 
    

   

   
   I hope my question was clear. Please let know if I can provide anymore information, and I hope to receive some advice soon.
   
   Kind regards,