You are most welcome!
The ones I have read I've borrowed from the library (public or Gurdwara) and forgot the titles (*shame*). Have a look around Amazon and see what you can find. Go for scholarly-type, not religious-type, because you'll get more facts and less bias.
For the life of Guru Nanak Sahib Ji, I recommend The Sikh Religion, Volume 1 by Max Arthur MacAuliffe. Max was a British public servant who went to Punjab to research, and published a collection of books about Sikh Gurus. By the time he was done, he had converted, and is possibly the first "white" convert to Sikhi. You can read it for free here
The Sikh Religion Vol. 1 Index or I'm sure you can buy one or all volumes. If you read it and want more volumes, they are all available to download, and I can dig up the link for you.
Sikhs are divided on the topic of reincarnation. The majority believe we are reincarnated until we are liberated and merge with Waheguru after death. A minority do not believe in reincarnation and believe we have one shot at liberation, which is merging with Waheguru in this life, and death is death. As you delve you'll come to your own conclusion. Sikhs do not generally believe in a strict system of samsara like Buddhists, and for the majority who believe in reincarnation and karma, karma has far less of an impact on reincarnation, unlike for Hindus.
I can't speak for many Eastern religions on meditation because I've only researched Sikhi. Sikhs place value on training the mind, and meditation helps with this.
Conquer your mind, conquer the world. As I'm sure you've already learned, Sikhs meditate with words like 'Waheguru', 'Satnam Sri Waheguru Ji', or meditate on the Mul Mantar. Personally, I put any talk about meditation with regard to the 'tenth door/gate', 'dasam daur', 'third eye' stuff in the 'woo' category. But that's just me. Meditation is a psychological process.
With regard to the God concept in Sikhi, yes, I feel that what you've gleaned from the videos is correct. Sikhs have various ideas about God, but most would agree that Sikhi is panentheistic. This means the Creative Force existed before creation, creation is within It (and hence It is within everything), and It will continue to exist once creation ceases to exist. Imagine the Creative Force is an ocean, and creation is a wave. The wave is formed of the ocean yet is a distinct thing itself, until it falls back into the ocean. The Creative Force is not very personalised within Gurbani, and when it is the Gurbani is usually employing a poetic technique of personalizing a concept so it is easier for us to relate to.
I hope I'm not bombarding you with too much information, or confusing you in any way.
Gurfateh