From the perspective of Theravada, can a Mahayana follower attain Nibbana?

I’m just going to say what I think from a Theravada’s perspective so don’t attack me in the comments. In the Mahaparinibbana Sutta, the Buddha said that if Buddhist monk or nuns practice the noble eight fold path then this world will not be empty of arahants.

Then Subhadda went to the Blessed One and exchanged courteous greetings with him. After an exchange of friendly greetings & courtesies, he sat to one side. As he was sitting there, he said to the Blessed One, "Venerable sir, these brahmans & contemplatives, each with his group, each with his community, each the teacher of his group, an honored leader, well-regarded by people at large — i.e., Purana Kassapa, Makkhali Gosala, Ajita Kesakambalin, Pakudha Kaccayana, Sañjaya Belatthaputta, & the Nigantha Nataputta: Do they all have direct knowledge as they themselves claim, or do they all not have direct knowledge, or do some of them have direct knowledge and some of them not?"

"Enough, Subhadda. Put this question aside. I will teach you the Dhamma. Listen, and pay close attention. I will speak."

"Yes, lord," Subhadda answered, and the Blessed One said, "In any doctrine & discipline where the noble eightfold path is not found, no contemplative of the first... second... third... fourth order [stream-winner, once-returner, non-returner, or arahant] is found. But in any doctrine & discipline where the noble eightfold path is found, contemplatives of the first... second... third... fourth order are found. The noble eightfold path is found in this doctrine & discipline, and right here there are contemplatives of the first... second... third... fourth order. Other teachings are empty of knowledgeable contemplatives. And if the monks dwell rightly, this world will not be empty of arahants."

In my opinion, Mahayana doesn’t have right view because they think arahants are lacking in knowledge or not free of lust, hatred or delusion so they don’t possess right view. Mahayana’s emptiness is not taught in Theravada’s Buddhism but in MN 121, emptiness is something that is not present just like your house is empty of a elephant or a horse but emptiness is not a key doctrine. The key doctrine is the four noble truths. Rebirth, dependent origin, eight fold noble path, anatta, anicca, dukkha are all included in the four noble truth. I’m not sure if mahayanists can even attain stream entry but THIS IS JUST MY OPINION SO DON’T ATTACK ME IN THE COMMENTS

There aren't any texts within the Theravada school that talk about what happens to practitioners of other schools. The closest reference I can find in it is in the Mahaparinibbana Sutta, which says;

Then Subhadda went to the Blessed One and exchanged courteous greetings with him. After an exchange of friendly greetings & courtesies, he sat to one side. As he was sitting there, he said to the Blessed One, "Venerable sir, these brahmans & contemplatives, each with his group, each with his community, each the teacher of his group, an honored leader, well-regarded by people at large — i.e., Purana Kassapa, Makkhali Gosala, Ajita Kesakambalin, Pakudha Kaccayana, Sañjaya Belatthaputta, & the Nigantha Nataputta: Do they all have direct knowledge as they themselves claim, or do they all not have direct knowledge, or do some of them have direct knowledge and some of them not?"

"Enough, Subhadda. Put this question aside. I will teach you the Dhamma. Listen, and pay close attention. I will speak."

"Yes, lord," Subhadda answered, and the Blessed One said, "In any doctrine & discipline where the noble eightfold path is not found, no contemplative of the first... second... third... fourth order [stream-winner, once-returner, non-returner, or arahant] is found. But in any doctrine & discipline where the noble eightfold path is found, contemplatives of the first... second... third... fourth order are found. The noble eightfold path is found in this doctrine & discipline, and right here there are contemplatives of the first... second... third... fourth order. Other teachings are empty of knowledgeable contemplatives. And if the monks dwell rightly, this world will not be empty of arahants." http://www.accesstoinsight.org/tipitaka/dn/dn.16.5-6.than.html

Which I think indicates that as long as the Noble Eightfold Path is present, you can expect to find enlightened beings.

There is an additional issue of what happens with a person who makes a Bodhisattva vow. According to the Theravada school, a Bodhisattva must complete three great eons of practicing the ten Paramis in order to attain Buddhahood, but attaining stream entry, the first stage of enlightenment would cause that person to pass into parinibbana within seven lifetimes. As a result, a Bodhisattva will not attain stream entry or higher until the time when they are almost finished. If a Bodhisattva engages in vipassana meditation before that point, then they will be able to progress to Anulomanyana, the knowledge in which one sees the four noble truths, but the force of their Bodhisattva vow will stop them from going any further and accidentally attaining stream entry. This information is found in the commentary on the Majjhima Nikaya and is referenced in one of the Ven. Bhikkhu Bodhi's footnote on MN81 which says:

"MA notes that bodhisattas (or bodhisattvas in Sanskrit) go forth under the Buddhas to purify their virtue, learn the Buddha's teachings, practise the meditative life, and develop insight up to conformity knowledge (anulomanana). But they do not make effort to attain the paths and fruits (which would terminate their bodhisatta career)."