Munni,
You have several questions into one. I thought you only wanted to know about Ahmadi view of Baba Guru Nanak. 
Anyway, the couple that I can answer:
**>>>>>but he said his message would spread to the ends of the earth, **
Your friend must be referring to the revelation of the Promised Messiah (as) that he received in 1891, and I quote:
*“I shall make thee known with honor to the ends of the earth and shall exalt thy name.”
*
This was a time when he, Hazrat Ahmad (as), had just initiated the Ahmadiyya movement 1889 and the persecution & opposition was mounting day after day and it peaked in the years ahead. Also, it is to be noted that at that time there were no Ahmadi missionaries outside of the Subcontinent. The Ahmadiyya Movement in Islam today has branches in up to 174 countries around the world & an estimated membership of 170 million. Contrary to common belief, the most number of Ahmadis are in Africa, India & Indonesia … but Pakistani Ahmadis indeed holds many recognitions.
You can read some overview of the Ahmadiyya Movement here: An Overview
**>>>> this same friend stated that Guru Nanak was in fact muslim. That he wore something that had the kalma on it, etc. **
This is true! According to Ahmadiyya belief, Hazrat Baba Guru Nanak is considered to be a pious Muslim leader who made peace between the Hindus & Muslims with his teachings. The cloth your friend might be referring to is called “Chola Baba Nanak”.
The Chola, or the cloak of Baba Nanak, is the holiest relic of the Guru and is preserved in Dera Baba Nanak, a small village in Gurdaspur District of the Punjab. This is a cloak which Nanak wore in his life-time and it is considered so sacred that his immediate followers took every care to keep it safe. The regard and reverence rendered to the Chola by the Sikh community is a testimony to the authenticity of the cloak. The words of Guru Nanak as contained in the Guru Granth Sahib (Sikh scriptures) were not collected until the time of Guru Arjan Dev, the fifth Guru, and therefore cannot be relied upon as accurate particularly as Sikhism had by that time assumed an attitude of hostility towards Islam. But the Chola is clear from this charge, because it was handed down by Nanak himself and has come down to our times in its original condition. It is commonly alleged that verses from different scriptures in different languages are written on the Chola. But this is not true. The verses chosen for writing on the Chola are quotations from the Holy Quran as revealed by photographs recently taken. The religion followed by the man can be none other than Islam.Source
Earlier it was believed that the Chola had verses from many different religions but Promised Messiah (as) took a special journey to Dera Nanak in Sep-Oct of 1895 and after persuading the Sikh guardians of the Chola, it was unwrapped in front of many witnesses and to surprise all the verses on the Chola are none other than Quranic Verses.
Sikhs believe that Hazrat Baba Guru Nanak didn’t wear the Chola but kept it because it was given to him as a gift from the then Caliph of Baghdad. Other Sikh members of gupshup can give you their part of the story a little better.
