Yes — I-FLAC ikhupha ikhowudi ngokufana ne-bit-identical kumbhali, ngoko naziphi na iindidi zokulungisa-ukuphinda ugcine izijikelezo azikho xabiso lokungathembeki. It is worth knowing before you overwrite an original you might need again.
No. Cima FLAC is free without an account, and nothing is added to the audio. The upload and the result are deleted automatically about 24 hours after the job, which leaves time to download the result.