The posts labeled with two or more techniques are more "advanced" than those labeled with just one, as it is expected the individual techniques have been mastered individually. Many selling writers (even best selling) have novels published with a lack of blending of the techniques - and many readers enjoy them. The long lasting, much reprinted, classics usually have a core of a blend of techniques so smooth that academics can't factor them back out to individual techniques. As a result, much academic work has been published labeling "the theme" of a given novel as something which it is, in fact, not. The thing is, the author often doesn't know what the theme of a given novel is until maybe 20 years after publication.
What you think your theme is, and what it actually is may differ. It is not necessary for the author to be correct, but it is necessary to be consistent.
Conflict is the essence of Story -- but theme is the essence of Art.
Here are posts on integrating the technique of "theme" with the technique of "conflict" with emphasis on Romance between highly contrasted individuals (such as human-alien)
Part 1 - Battle of the Sexes
Part 2 - A Grifter, A Shyster, and a Priest Walk Into A Bar
Due to a numbering error, there is a Part 2A about Designing A Conflict
Part 3 - Battle of the Generations (the Generation Gap)
Part 4 - Battle of the Orville TV Series
Part 5 - DEFIANT by Dave Bara (a novel worth studying)
Part 6 - A Character Under Influence
Part 7 - Romance Without Borders