Whilst Europeans were not exploring the African interior to the same extent that they would during the Scramble of the 1870s and afterwards, their relative isolation on the coasts of the continent was not the same thing as being unable to venture into the hinterlands. Let me give you some context as to why an Englishman (if indeed that is where Jonas Wright was from - I can't find any further information on him!) was in the African interior.

Many European individuals sought riches and fame within the interior, drawing upon tales and stories from African traders as to the mountains of gold that lay on the surface many hundreds of miles inland or the spices that grew in abundance with no owners. The rumours of Prester John, the infamous Christian king who supposedly ruled a whole swathe of Africa under the word of the Gospel, drove many inland along the multitude of rivers and tributaries, hoping to be the first to find this man and thereby connect the great Christian empires. In 1487, Pêro da Covilhã and Afonso de Paiva, two Portuguese envoys travelled overland from Guinea to try to find an Indian sea route and Prester John. Pêro da Covilhã reached Ethiopia where he was detained. Similarly, on his second journey of 1484-86 Diogo Cão, a Portuguese explorer and navigator, also ventured inland in search of Prester John, navigating up the Congo River to Matadi. He left a pillar near Lelala falls to mark his progress.

In 1552 Jaoa de Barros, a Portuguese civil servant and historian, compiled an account called Decadas Da Asia of the history of Portuguese involvement in Asia, the discoveries, conquests, stories, people and regions themselves. Despite being stationed in Guinea, he himself never ventured to many of the places he mentioned, often relying upon the stories of others who had. Portuguese soldiers, merchants, explorers, as well as African and Arab traders were all questioned and their accounts compiled into the astounding 4 volume work, the last one of which was not published until 1615, almost fifty years after his death. Many of these Portuguese explorers he questioned had travelled far into the interior with their African companions. The Swahili traders who frequented places well away from the European posts, such as the Zimbabwean highlands, provided the first account of Symbaoe, or Great Zimbabwe, and in the same account de Barros notes that Portuguese explorers had reached nearby regions. The Muatapa did have trade links with the coast, through the Swahili traders, and the ability of Europeans to travel with these traders would certainly have been feasible.

Missionaries were also present in the region, particularly Jesuit missionaries such as Gonçalo da Silveira. His expedition up the Zambezi in 1560 saw him travel far into what is now Zimbabwe, reaching the capital of the Monomotapa, where he stayed until his death.

All of this means that an Englishman in the African interior in 1632 would not have been too unlikely - rare, maybe - but not impossible. European contact with the Africans of the interior was far more extensive even by the end of the sixteenth century than is commonly assumed.

It is also crucial to note that just because the Wavuma were found on the northern shore of Lake Victoria in 1875 does not mean that is where they were two hundred years earlier. The history of the Ngoni (of which the Wavuma were one group) is one of migration. Large scale migration was relatively common place meaning that African societies may well have been located closer to the coast than they were in 1875, meaning their interactions with Europeans may have been more frequent than could be indicated. Certainly, if King Btesa's group had been located maybe one or two hundred miles east, they could have come into contact with Portuguese traders via the Swahili routes. This could also ensure that if somebody had gone looking for 'poore Jonas', and come into contact with King Btesa who provided him with Jonas' possessions and skin, as well as an explanation as to what had happened to Jonas Wright, the contact could have been made through these trade routes.

I am by no means an expert on pre-colonial Africa ( I focus on the later periods!) but I do have a fairly good understanding of European exploration and colonisation, so if something doesn't make sense, fire away!

Never heard of this person, incident or that Wavuma people, but at this time Zimbabwe was dominated by the Mutapa or Monomotapa Kingdom. By way of the Zambezi, the Mutapa had close trade and diplomatic ties with the Portuguese posts in Mozambique, and viceversa. It is then conceivable that if an Englishman landed in Mozambique and wished to visit Zimbabwe he could do so that way. You'll have to wait for someone with more knowledge for a more detailed answer though.

Link to /r/books post?