I am not aware of any Android music player that have been specially focused on Classical music, but if you were refer to the Composer - Conductor type music management, I suggest you organize your music folders specially for this purpose, and that will allow you to adopt different DAP without causing a lot of problem.
I think a simple two-layer structure will serve the purpose.
First level Folder: name of Composer
Second level Folder: name of Conductor + Album name + Year (optional) + Label (optional)
File name: CD number (optional) + Track number + Track name
I prefer putting music files from multi-CD albums into one single folders because this will allow you to to listen to the complete album even when you DAP does not support play through folder feature.
Again, I am not familiar with Classical music, so what I assume will work might become a joke in the eyes of the experts, I welcome comment or alternative suggestions, or you can post your example on items that can't be organized correctly under this structure, I am sure we'll have another expert helping out promptly.
I have tried Foobar on Android, it works very well, but please understand Foobar only goes into Android market recently so don't expect the Android version of Foobar will be as comprehensive as the desktop version in near future. I am not familiar with JRiver, tried Gizmo briefly but don't really like it. Both Android app are not memory hungry so they should work satisfactory with i5.
i5 offers BT but unfortunately this is not the something that we are proud of because i5 don't support aptX. Sound performance is OK but not great. I have discussed the issue with some audiophile friends who want to use i5 in his car, and he finally come out with a solution by using the Line out of i5 to connect to the AUX input of his car audio system, and then he bought a BT remote control and mo unt that on his steering wheel. I find a similiar remote control on Amazon for your reference.
https://www.amazon.com/iSimple-Portable-Wireless-Smartphones-Bluetooth/dp/B00KPZN5UC