Foreign language textbooks certainly like to employ all kinds of typeforms to direct the attention of the reader, and as you've noticed, this can introduce a lot of clutter into the foreign language material.
In my response, I will refer to the material you're inquiring about as a conjugation chart or verb chart (depending on what the textbook calls them), rather than a word list. The Vocabulario box on the right of the page is an example of what Braille Formats considers a foreign language word list, and the formatting of a word lists is covered by BF2016 section 17.7.
Braille Formats 5.1.2 states that font attributes that add meaning to the text must be retained. In this case, does the highlighting provide necessary information in all places it is used? In my opinion, in the explanatory text, the highlighting does have meaning or the teacher may refer to the different colors of highlighting. However, in the verb chart, it is self-evident which words are spelled with "ue" and which with "u". Adding highlighting to the letters "ue" and "u" does not add useful information and may interfere with the reader's ability to read the word in its normal form. When changes are made to the print format, it is never wrong to add an explanatory transcriber's note. For instance, "In the following verb chart, green highlighting on the letter "u" and orange highlighting on the letters "ue" have been omitted."
The bold within the words in the verb chart does hold information which is not explained in the surrounding text (it separates the stem from the ending of each form of the verb), so I would recommending retaining the bold.
If you felt the highlighting within the verb chart did help the reader by establishing the pattern of spelling changes, you could follow BF5.8 (and example 5-16). This gives the transcriber the option of showing the material twice: once without indicators and then again with indicators using a transcriber's note to alert the reader of the format. I think the way you have brailled the chart in your sample might be one solution (provided you place the words with the typeform indicators in the runover position for the column). A possible TN would be: "In the following verb chart, the words are shown first without emphasis and then repeated with all indicators used." Theoretically, you could show the entire chart twice, once without the indicators and once with them in order to avoid having runovers within the chart.
For the phrase jugar a + sport, I would suggest placing this in cell 3-5 as displayed text separated from the surrounding text by blank lines. This format would allow you to omit the boldface because the shift in language is indicated by the change in margins and blank lines. The green highlighting on "a" as well as the green font and italics on the word "sport" are significant and would be retained:
For the section with sentence/translation pairs at the bottom of the sample, "Ignacio asks Roberto:" and "Coach Castillo asks:" are part of the paragraph above and should be placed in 1-1. The Spanish and English sentences would be treated as displayed material because they are set off from the surrounding text by blank lines and by a change of print margin. I would place them in 3-7, 5-7 as you have them, just with the addition of blank lines above and below.
Please let me know if you have any further questions.