The angel collar is in a set of 4 items for 10C$. The blue floaty wings are in a set of 4 items for 10 C$. The fairy wings are 3 C$. Pricing the set items at ~2.5 C$ each (10 / 4 = 2.5), your side is 8 C$.
[edited pet values based on an extension mistake]
Using the CS trade extension:
2014 UC - 2-3 C$
2018 C - 0.5-1 C$
2021 VUC - 2 C$
2025 OMGSC - 0.25 C$
2 unknown rarity pets - 1 C$ each; values will likely change once rarity is updated
So if you value the unknown rarities at 1 C$ each, you get a total of 6.75-8.25 C$ on their side. It's technically within the range, though on the lower side. I would say go with which side you want or maybe ask them to add a little bit. The items are in the store currently, so they don't have any special value.
In the future, you can use this thread for trade help:
Forum/viewtopic.php?f=135&t=5012039