I would suggest adding Wesleyan to the list even though it is not on the “official” list of Math LACs. Wesleyan has a small graduate school over the STEM part of the LAC which allows advanced STEM undergrad students to enroll in grad courses and even complete a free 5th year graduate degree. My son has just finished his math major requirements and will start graduate level math courses this fall as a junior. With the open curriculum and few GenEd requirements, he is able to triple major in math, physics and computer science.
Since there is not a large grad school population, he has been able to be a paid TA for upper level math, data science, physics and computer science courses. He is currently on campus doing paid summer research directly with a math professor who will continue as an ongoing mentor working together on research towards his eventual master’s thesis. He also will start a math-heavy quantum physics research project this fall which he recently proposed directly to a physics professor.