Never tested yet breadwallet but for me i still trusted to use mycelium if i wanted to use wallet in my android phone..
Your phone will be always safe as your phone never root because its decrease your security of your phone and possibility the can monitor or getting the hide files of your wallet.
Install antivirus can help protect your phone from any malware and viruses..
as of now never experience any problemwith my phone and always updating my ESET antivirus because i can set the security into quarantine if it detected  some suspicious apps in my phone..
The good thing you can easily understand how mycelium work and you can backup your 12 word phrase.