When applying to any school ED, make sure that it is likely be affordable. Talk with an international admissions officer to see if getting a financial aid pre-read is possible.
Tufts does meet full financial need, and it’s unclear whether it is need-blind or need-aware for internationals.
https://admissions.tufts.edu/tuition-and-aid/applying-for-aid/international-student-aid/
According to the most recent CDS, 168 of 588 international undergrads receive fin aid, around $60K on average (H6). https://provost.tufts.edu/institutionalresearch/files/CDS_2018-2019-Final.pdf
Lehigh is need-aware for international students and does not meet full need. Lehigh should be considered a reach, as admissions is fairly competitive and you will require financial aid to attend. https://www1.lehigh.edu/financialaid/faq
According to the most recent CDS, 101/459 Lehigh international undergrads received on average nearly $49K in aid. https://www.lehigh.edu/~oir/cds/lucds2018.htm
Lehigh COA is around $75K/year, not counting travel and health insurance, so on average, an international student receiving fin aid still needs to pay around $30K per year.
You should consider any US school where you need financial aid to attend to be a reach. Safety schools will most likely be located in your country, or where you meet acceptance criteria based solely on stats. A safety can only be a safety if it is affordable. Good luck.