Fiverr seems to work better with more specific and exact Gigs eg
I will make you a pink paperclip tends to be easier for most people to understand than I will make you any kind of paperclip (yeah, but does that include pink ones?).
So, a Gig where you draw a Line Art version of a certain orange-faced ex-President is clearer than I will draw ex-Presidents in any style you like.
Once you decide on the focus of the task, you can then use the other two options to add fancier versions so you can start with
I will draw you a delightful* daffodil that delivers line art (only) in the basic version
The mid version adds some color
The top version adds full background and full color overall
Each costs more as you take more time and the customer gets a better picture - assuming they need the colors.
Make it very clear in gig images what the three options will be like. One artist here has a few images that show all versions on one slide to make it really clear what each investment will deliver. Good thinking.
To answer the Styles Q, I think to make each core Style a different gig so it is easier to handle keywords for each type as someone who wants cartoons may not want oil paintings in the style of Manet.
*take care with emotive words as my idea of delightful may not be yours but this alliterates and I have a weakness for alluring alliteration