25% is not too much. You want to maintain about 5-10% soil organic matter - BUT: Commercial compost products (any compost, really) have a significant amount of water, first. And of the dry matter, only a percentage is organic matter. That will further decompose as it becomes semi-permanent soil organic matter. So 1/4 compost in your mix is fine. You could probably go higher than that - 1/3 for example. The more you add the more shrinkage you will have so be prepared for that.

Compost products vary seasonally and according to who made them and what they put in. It's hard to say whether any given manure compost is better than the mushroom compost next to it on the shelf, or vice versa. My approach is to use a couple different ones. If I'm getting multiple bags I'll usually get some of the cheap stuff (after checking it to be sure it's not full of soil or sand but is arguably 'compost'). And maybe a couple bags of something nicer. Composting brings various organic matter inputs toward a similar end product but there will be some differences. By varying the inputs you get a good variety of organic matter and minerals. You kinda get what you pay for: cheap stuff has less organic matter and more soil, and the most expensive is not necessarily that much better than the middle. And always inspect even if you have to poke a discrete hole in a bag.

Sand is not necessary and peat moss has no nutrition and is often trucked long distances. It is also acidic, which can be nice if you have highly alkaline soil, but in most cases it isn't necessary. Plain old compost is dandy.

Thank you very much. That's very helpful.