Max file size; Using focus to find untagged

I have two unrelated questions:
(1) What is the maximum size of an ALAC file Roon can import? I have ripped some blu-rays with file sizes up to 900 Mb per file. I can play them on iTunes and on my Mojo-Poly, but not on Roon. Any explanation? Is it size or max bit rate or something? It’s a bummer I cannot use Roon for really hi-end audio.

(2) I have hundreds of albums without tags. Is there a way to use focus so I can identify them among the many 1000s using focus, and then tag?