I would be very wary of claiming that Edith Grossman, or indeed any other translator, used any particular theoretical 'method' when translating. You might well find a few examples in a book-length translation that could be called 'foreignization', but what about the rest of the translation not included in your examples? What 'method' or 'theory' would explain the rest of it?
In fact, Grossman has made statements like these in interviews:
I have read very little theory of translation. I never can figure out what the theoreticians are talking about.
Do you believe in a theory of translation?
EG: I find some theories very interesting while others don't make much sense to me. When I began to teach the workshops, I realized that general rules cannot be applied in an invariable way. I think that solutions to the most interesting problems in translation ultimately depend on the translator's intuition. For example, if part of the meaning is likely to disappear in the translation, there are times when I prefer to add a few words that may not exist in the original in order to convey the full idea.
By the way, I found those interviews by googling for the combination edith grossman translation theory interview. If you do the same search, you'll find the two interviews I quoted above plus many more.
I also recommend reading Edith Grossman's book Why Translation Matters (Yale University Press, 2010) to find out more about her own views on her working methods.
Gregory Rabassa is another prominent translator of García Márquez's works into English. His memoir is entitled If This Be Treason: Translation and Its Dyscontents (New Directions, 2005). In it he discusses how he translates, and he devotes a section to each of the authors whose works he has translated, including García Márquez.
Two more recommendations for discussions of the relevance (or lack thereof) of translation theory to the work of translators:
1) Boase-Beier, J. "Is Translation Theory of Any Practical Use?" In Other Words 41 (Summer 2013): 76-78.
If you cannot find that journal in your university's library, you could try contacting the publisher, the British Centre for Literary Translation at www.bclt.org.uk/publications/in-other-words/.
2) Chesterman, A. and Wagner, E. Can Theory Help Translators? St. Jerome Publishing, 2002.