Oh I forgot to read the 2nd part of your question. Sorry!
I believe an online player definitely has an edge over a live player if they are equally skilled. If a live player never played online they will be in for a surprise at the difference. Online you can play multiple tables at once, the volume of hands you see are WAY MORE, people use HUDs to see the stats of others (TAGs, LAGs, rock/nits and etc.) Also HUDs are like "gameshark" mode. A lot of the HUDs can show you your win odd% pot odd% all of your outs INSTANTLY. It takes a lot of the guesswork out for you. Plus there's no LIVE tells
Live & online are two completely different realms IMO. It would take some adjusting if you never played online. Carbon has a free HUD. It's actually really good IMO and it's F-R-E-E. Since you only have a $20 bankroll. I dunno if you're tight on money, but Carbon's poker odds
calculator is legit for its free price. It EVEN tells you if your hole cards are EV+ lol.