Is Fr. Bourgeois still a Maryknoll priest? Yes. For now.
If excommunication achieves its medicinal purpose and Bourgeois repents of his anti-ecclesial conduct, his reconciliation with the Church would be prompt (1983 CIC 1358). In contrast, having also to formally readmit a reconciled priest or religious offender to the clerical state and/or to an institute of consecrated life, would only slow down that fundamental process of reconciliation, impeding the effectiveness of the excommunication in the first place. So in a situation like this, canon law does not call for dismissal or expulsion immediately, though the restrictions on Bourgeois' priestly and official society activities are probably severe (e.g., 1983 CIC 1331).
Make no mistake: if Bourgeois does not repent, additional consequences can flow from his contumacy (1983 CIC 1326 and 1393), including dismissal from the clerical state and expulsion from consecrated life. But there is time for that. Not much time, I have a hunch on this one, but some at least.
Till then, prayers for Bougeois' reconciliation are in order.