There is a fundamental problem in attempting to understand pre-conversion, Germanic belief systems. First, there are too few sources - as you indicate. This causes the connecting of dots in ways that may not yield accurate results: an obscure reference here is explained by a problematic source there. While there are, as you say, many Norse sources, most were written after conversion - sometimes after a century or more. These attempts to recall the pre-conversion world are extremely valuable, but they are not without their problems.

In addition, scarce sources (the Norse sources are hardly as abundant as we would like) often result in a single explanation of a story or a belief as being definitive for the entire region, spread over centuries of pre-conversion beliefs.

Ethnographic work and folklore gathering demonstrates that belief systems in non-literate societies are typically fluid. They change from place to place and even from person to person, and they are susceptible to change over time. So it is problematic to take a thirteenth-century Icelandic source for a pre-conversion story or belief and to assert that the insights that can be gained from this single gem is not only unaffected by conversion and the two or three centuries since conversion, but also that these insights can be applied to all of Scandinavia.

All that said - and with a full acknowledgement of the problems involved - the only way to understand pre-conversion Anglo-Saxon belief systems is to engage in the process of connecting these remote and problematic dots. It is not a perfect system, but it is the only one we have. There does seem to be a shared arena where many of the same players acted out their roles in what appears to be similar ways. There may have been shifts in emphasis as to which supernatural entity was more important here rather than there, but attempting to draw definitive conclusions is not possible in any real sense. Those who would reconstruct the pre-conversions Anglo-Saxon belief system are working more in the realm of fantasy than objective social science. But we are standing on a far better foundation than when attempting to understand Neolithic belief systems, so things could be worse.

In short, I'm not sure I would agree that all Norse-speaking peoples shared all the elements that we ascribe to their religious practices and beliefs. Did they all (spanning all the geography and just the two or so centuries before conversion in the classic Viking period) share in the idea of Ragnar, the nine worlds of Yggdrasil or any of the other stories and concepts? Frankly, I doubt that. And given that, can these ideas be extended to the pre-conversion Anglo-Saxon world? Only with a great deal of caution and caveats.

There was an answer proved here that was deleted for lack of discussion/development much beyond citing a source. The site in question is a wiki article, which isn't horrible and has some valuable information. Many of its sources are dated and emerged from the Romantic period when the yearning of many enthusiasts drove speculation beyond what could be known with certainty, but the site presents a great deal of current thinking and attempts to reach beyond Jacob Grimm and James Frazer. Of course, emotional yearning still drives the speculation and devotion of many enthusiasts, so questions like yours attract neo-pagans as well as the intellectually curious and academically motivated.

While the wiki site has merit, it is important to understand that the more general the conclusion, the more one is likely to be flying at 10,000 meters above the ground and details become ill-defined. It is an interesting process to attempt to reconstruct a proto-Indo-European belief system, and remarkable advancements have occurred. Clearly, whatever was going on several millennia ago was a factor in how diverse later groups viewed and approached the supernatural. There were likely other influences and there was considerable drift. While it can useful and a great deal of fun to consider the beliefs and traditions of this prehistoric proto I.E. world, how that legacy reaches across the millennia to manifest in the specifics of the pre-conversion worlds of either the Scandinavians or the Anglo-Saxons is problematic. Some of the insights gained present intriguing questions and sometimes some information, but too often it is rather like chasing a wisp of morning fog. Sooner or later the heat of the sun will cause it to disappear.

I can only support the above comments. As an archaeologist working with Iron Age Scandinavia, I can add that archaeological evidence is another vital source to studying beliefs in these societies, as it gives valuable insights into people's actions and material culture. And, the current archaeological data only underlines the variability in ritual practice and traditions mentioned above. For example are burial practices extremely varied in this period, both between and within different time periods, regions, and communities. This indicates that there were many different ways of performing ritual actions, for different purposes, being understood differently by different people. The concept of one "Norse" belief system and what defines such a system has been challenged, as mentioned, and comparing Norse with Anglo-Saxon beliefs is thus by many regarded as a futile exercise. Still, the similarities cannot be avoided, and it is not unreasonable to claim that there may have been close connections. But to identify and find evidence for those connections, and what they entail to our understanding of past people is a different matter. We who are interested in the past are nevertheless incredibly curious and persistent people, and new things are found every day, so I won't be surprised if the relationship between the different mythologies may become gradually clearer in time.