Is there a way to reduce homocystein and Lipoprotein(a), either through diet, exercise, nutrition or combination of them?
Yes, there is. The same dietary and lifestyle recommendations we have been discussing here would be recommended.
Homocysteine levels can be elevated if someone's diet is deficient in folic acid, B6, and/or B12. A healthy diet would provide these in adequate amounts and if you someone choose to follow a 100% vegan diet which included no foods fortified with B12, then they could easily include a B12 supplement.
If you look at a typical American diet, it is often very low in folate (which is found in "foliage" like grean leafies). Folate has been added to the food supply and one of the nutrients added in the enrichment process. However, a healthy plant based diet easily supplies 2x or more the needed amounts.
While it is often said that diet will not effect lp(a), this same diet can lower your levels. However, in the first case scenario you presented, total cholesterol is (116) and LDL (62), i would not worry about lp(a).