1. "-vi" instead of "-ci"
You can do it whenever you want; they are exactly the same, it is just an issue of what sounds better to you (I tend to prefer "-vi" but "-ci" is more common). For example "rinunciarci" already has the sound "cia" so "rinunciarvi" might sound better; conversely "viverci" sounds better than "vivervi" in almost all cases (unless you explicitly want to repeat the "v" sound for poetic/musical reasons).
2. "Gli esperti consigliano di acquistare carne ovunque sia possibile verificarne la qualità."
If you add a conjunction, you change the meaning of the sentence.
As it is now, it means that you should buy meat (only) where you can verify its quality, if you say "Gli esperti consigliano di acquistare carne e, ovunque sia possibile, verificarne la qualità." it means you should buy meat and, where it is possible, verify its quality (but it is ok even if you buy it from a place where you cannot verify its quality).