Because its movement was primarily charismatic rather than doctrinal, Early Pentecostalism does not seem to have had a defined policy regarding the providential significance of the epidemic and how Pentecostals should respond to it. Moreover, by 1918 there were already two major Pentecostal denominations in the USA as well as many smaller or informal groups. This article reports several pertinent facts based on the articles from the Christian Evangel, the newspaper of the Assemblies of God:
Although they believed in healing, Pentecostals did not claim that their faith in God would necessarily protect them from the disease. However there were exceptions, as some Pentecostal ministers taught that God had miraculously protected a particular congregation (at least in the beginning of the pandemic).
The Christian Evangel published many healing accounts from ministers. However, it also included a list of prayer requests, many asking for prayer for themselves or their children who were dying of influenza.
Churches and ministers complied with health department mandates to close their meetings and quarantine those who were sick. They recognized that they needed to protect people in the cities they lived in. On several occasions, ministers canceled revival meetings because influenza was spreading across the town.
Yet, believers also went to the homes of those who were sick to pray. Some reported miraculous answers to prayer. They also ministered to the dying.
Unfortunately the OPs questions cannot be completely answered based on the information readily at hand. However the above summary gives a general sense of the matter: like other Christians, early Pentecostals responded to the influenza pandemic of 1918 through healing ministries, prayer for the sick and comforting the dying. They complied with health regulations, including canceling church services and evangelical meetings. They believed in the power of healing prayer but did not generally insist that their faith would protect them from the disease.
The OP asks for primary sources. Please refer to the linked article above for several of these.
This article deals with the response of overseas Pentecostal missions associated with the Faith Tabernacle Congregation.
This article deals with Indigenous African Pentacostalism
I was not able to find anything from the Church of God in Christ about this.