Well I can answer your 1st question. If by difficulty you mean technical difficulty, the path from Cojzova hut to Grintovec is probably one of the easier, if not the easiest, paths in Slovenian high mountains. From Grintovec to Skuta I know two variants. In any case you have to go from Grintovec to Mlinarsko sedlo. This part has some pegs and cables and is somewhat exposed in places but nothing special for me. At Mlinarsko sedlo you can decide whether to go over Dolgi hrbet or not. The first variant is among secured climbing paths and is slightly overhanging on one very short section. Otherwise, if you're used to walking with pegs and cables, no big issues. Regarding self-belay kit and helmet, you decide if you need them. You can get there without both. Once over Dolgi hrbet nothing special. The second variant goes somehow under Dolgi hrbet (at Mlinarsko sedlo turn right) and as far as I remember it doesn't present any special difficulties. Once on Skuta you have several variants to get to Cojzova hut (besides returning the approach way). One is to start returning the same way you came to Skuta and then at the junction where you can go to Dolgi hrbet or Cojzova hut, head towards the latter and not towards Mlinarsko sedlo but over Velike pode towards bivouac under Grintovec and on to Cojzova hut. The path over Velike pode can be quite annoying in dense fog in my opinion. From bivouac to hut there are pegs and cables again in one or two places but nothing too demanding. The other, I think somewhat harder variant, is to descend from Skuta to Male pode and continue towards bivouac under Grintovec and on to hut (don't know this path). Regarding hiking time, which is somewhat taboo on this forum sometimes, if you're reasonably fit I think it shouldn't take more than 5 to 6 hours hiking + snack/s. Could be more or less. Depends on the path you choose and on... Have a safe trip.