How to find your private key with your 12 Word Password Phrase and the depositing Address?
The 12 words encode a seed that can be used to derive bitcoin addresses. There are an infinite number of derivation paths you can take using any one seed, so knowing the right derivation path will be necessary to recover your funds. 

A quick google search tells me Mycellium uses the BIP44 derivation path: m/44'/0'/0'/0

So you just need to find some software that allows you to specify the path being created, and point it to the correct one. 


  I've been speaking with the Android developer and he's been discussing that I will need to keep creating new accounts and depositing coin to each new account so I can create a new account until I find the account with my bitcoins.


You most definitely do not need to send any bitcoin to any wallet you generate, in order to determine if it is the derivation path you are looking for. Upon being supplied the correct path, the wallet should show you your transaction history as per normal, as long as it is correctly synced with the network.