I think it would be useful if I painted a picture of Ethiopia at the time of the early crusades.
The late sixth and seventh centuries were difficult in Ethiopia, just as they were in Europe and western Asia. The plague of Justinian began in the hinterlands of Ethiopia and hit Aksum as hard, perhaps even harder, than it did the Mediterranean world. Kaleb's war in Yemen put a strain on the imperial treasury, which was already drying up due to the larger realignment in trade as the Red Sea was shafted in favor of other routes. With that trade drying up, coinage stopped and Greek fell out of use. The capital city of Aksum was abandoned; its soil exhausted. Later Negusa Nagasts governed from mobile tent capitals.
However, by the later 9th century Aksum had a new permanent capital in the city of "Ku'bar," as attested by Muslim authors. Abyssinian "kings" still payed tribute to the Negusa Nagast, who continued to rule over a large area in a decentralized system closely resembling the Aksumite kingdom. Muslim writers indicate that "Habashat" (the name by which the Arabs referred to Ethiopia) still controlled coastal areas, though Muslim kingdoms were beginning to encroach on that area. The focus of the Ethiopian kingdom, however, shifted south, into the highlands.
Trade continued to flourish; the country still possessed abundant agricultural stores, gold deposits, exotic animals, and a number of other valuable goods. Unfortunately, the expansion of the Muslim caliphates cut off most Ethiopian contact with European Christians, limiting trade to neighboring African and Arab polities. The patriarch in Alexandria continued to appoint a bishop to the Ethiopian Coptic Church, but only with the approval of the Muslim Egyptian governor. The story of Metropolitan Severus, appointed by the Patriarch in Alexandria in 1073, is worth relating. Severus apparently tried to please the Egyptian Amir by building Mosques. He was arrested. The Amir sent letters threatening to demolish the Ethiopia Churches, to which the Negusa Nagast replied ""If you demolish a single stone of the churches, I will carry to you all the bricks and stones of Mecca . . . and if a single stone is missing I will send its weight to you in gold".
During this "post-Aksumite" time period, which stretches from the end of coinage in the 610's or 630's to the establishment of the Zagwe Dynasty in 1137, Arab writers maintain a sense of respect for the Ethiopian state. Abyssinia was not a push over; it retained its marshal spirit of the Aksumite times. Muslim rulers hesitated to push Ethiopia, not just because a late Aksumite king had offered shelter to early followers of Muhammad (though this was certainly taken into consideration) but because such a course of action would have been foolhardy. However, the Ethiopian state did not go entirely unchallenged. The legendary Queen Gudit is a historically attested person, a foreign Queen who seized power in Ethiopia and ruled for around thirty years, from the 950's through the 980's. Ecclesiastical histories indicate that sometime before 1003 the Coptic Church and native Ethiopian monarchy was restored.
I don't have any good information on Ethiopia in the 11th century, though the period of relative quiet would seem to indicate that Ethiopia had rebuilt and was perhaps flourishing after the depredations of the foreign queen. The First Crusade took place during this period. Keep in mind, as I mentioned above, contact with Christian Europe was almost non-existent. Coordinating some sort of attack on the Seljuks would have been close to impossible, to say nothing of sacking Mecca. Then the two decade period beginning in 1131 was a bad time for Ethiopia; the land suffered from pestilence, famine, and drought. During this time, the Zagwe Dynasty was established. Safe to say, they would not be coordinating with the second batch of crusaders, even if they could contact them.
Hopefully this has been informative; if you have any other Ethiopian questions ask, and I will do my best to answer.