I'm not sure if you will accept this as an answer, but I will deflect your question on Tosafos by pointing out that this is not Tosafos' chidush. It is a direct quote from a censored gemara in Shabbos 104b which Tosafos in Chagiga referenced. 

The missing gemara there says אמו מרים מגדלא. 

Tosafos there says the people under discussion lived during the time of Rabi Akiva, so perpetuating the confusion and coincidences of the names and personalities under discussion.