Witch Girl answers:
Work with them in different roles? Angels often work well in protective, guiding, or elemental roles, where goddesses will have different roles depending on what you're doing, but often more related to the actual work you're trying to do or in more of a teaching role. It would probably depend largely on which goddesses and angels you're working with, but I don't see why you couldn't work with both.
What are angels? Angels are messengers, plain and simple. The word "angel" comes from the Greek "angelos" meaning "messenger." That's all it means. The term "angel" has also been extended to protectors (guardian angels) and to certain elemental beings. The watchers, guardians of the watchtowers, and gatekeepers aren't angels (although, if you think that all unembodied entities are either angels or gods, then you'd have to call these being angels, but then you would also have to call all faeries, elementals, ghosts, demons, etc "angels" as well).
The Guardians, Watchers, Gatekeepers, etc. are energies/entities whose purpose is to mirror your own intentions back to you, ensuring that you are truly ready to enter the other realms before you go causing damage there. They often invoke fear, terror, and awe in those who have impure intentions or who are simply not ready to travel beyond their "towers." Their nature is not "to keep humanity from progressing," but to show a mirror of the self. Those full of fear for nature and feeling that it is an evil thing to be overcome, will feel and see terrifying things when they try to tap into nature's ways. Those who wish to enter into communion with nature and live harmoniously, to better themselves and the world around them, will find love and kindness and balance from those same guardians. If you ever find yourself filled with fear, put up your guards, get out, then try to find out, if the negativity really comes from you and where it originates.
About angelic entities intruding... If you're putting up protections, you don't have to worry about this. If you have any entities, whether they're calling themselves angels or not, intruding when you don't want them to, you just tell them to get lost. They go away or at least make themselves less obvious to you. Oftentimes, a spirit that first comes to you in visions or dreams or rituals is a spirit that has been with you all your life. It's not like they're "intruding" all of a sudden, just making themselves known because you're ready to know about them. If they feel like negative intruders, then getting rid of them is a good idea. Angels don't ever feel like negative intruders, though they may be unwanted at certain times. Just like you can tell a person to leave you alone for a while, you can tell a spirit or angel or whatever to do the same. Still, it shouldn't be an issue with angels.
It has been my experience that entities in the spirit realms are not able to really "lie" like we can here on this plane. They may hide their full intentions at times, but if you ask them point-blank, they will tell you. If you say, "what are your intentions with me?" you should get a real answer. Oftentimes, however, yes or no answers are the best, as there is no guesswork. Riddles and rhymes are par for the course and really shouldn't be considered a method of deceit.
Messengers aren't always the bringers of good news. You have to accept the news they bring, even when it is devastating. If they stick with you through the hard times, they're good friends, just like your human friends who stay with you.
