Vatican Reminder: Sspx Ordinations Are Illegitimate

[Vincent Vega]

In short:
Validity refers to whether or not the thing "took" (i.e., whether or not they actually became priests; whether or not it's the Eucharist or just a little circle of bread; etc).
Licitness refers to whether or not the thing that happened was permitted to happen (i.e., the Eucharist confected by a suspended priest; the ordinations in question; etc.).
It is possible for things like this to be valid and licit, valid and illicit (as in this case, where the ordination took but was not supposed to have been allowed to happen), or invalid and illicit (I don't think it's possible, by definition, for something to be licit but invalid).