I am not the expert by any means, but I would believe that some 'dark time' would benefit your plants. Until this year I have always grown from pre-started plants, like the Burpee varieties and such. This is my first year from seed and the pic below is at exactly 22 days from seed in soil (for the oldest ones of the bunch in the pic)... There are young ones too, and I'm still germinating as well. So your 1 month olds look roughly similar to my nearly 1 month olds.... I'd say you're growth is doing fine, besides the previous mentioned problems. (Sorry, still new to seedlings, so no really good advice) I am not a strict organic though, and add a VERY weak dilution of MG tomato fertilizer to mine after they get the first true leaves.

Yes you will definitely need to pot them up to a larger container ASAP. Broccoli grow very fast from the 3 week stage on. You don't want them to get root bound in those little containers as it can cause the broccoli to produce little 'button' heads rather than nice large heads. I use the 18 oz. solo cups for Broccoli and they work pretty well except they can get a little top heavy so I need to take care to make sure they don't topple over when hardening them off in the wind. I think you will also want to plant them ouT much sooner than 3-4 weeks from now. I try to plant out around 30 - 35 days max from seeding and often the plants are bigger than I would like at 35 days. They grow very fast during the hardening off period! The worm castings may give them all the nutrients they need but you might want to give them a diluted shot of fertilizer after potting them up. For seedlings I use the Miracle Grow liquifeed veggie fertilizer mixed at about 1/4 strength.

If you are referring to the very slight discoloration on the tips of a couple of leaves, it is nothing to concern yourself about. It can arise from a number of situations, including bruising, lack of adequate light or an abrupt change in light conditions. Cacti and succulents are very easy care plants and GW has an entire forum devoted to them. Questions about light, potting soils, watering needs and fertilizing are best addressed there.

Benjamin NP, and I hope everything is OK... (I apologize for the following lengthy reply.) nomen summarized it well. If you are sure it is not any mechanical injury (that would be the less danger to your plant), it could be waterlogged leaves. Usually, leaves slowly yellow, are soft & 'plump' (too much water), and fall off still soft. That should be solved with good drainage and watering only when just about completely dry. You could help yourself with a bamboo skewer or skinny dowel or even pencil - stick it deep into pot and, halfway or deeper, trying not to damage roots. If it comes out feeling cold-damp when touched to your cheek or top of your hand, and/or with small particles sticking to it, soil is still wet and do not water yet. Any succulents you have (or will add :) will do best in grittier potting mix. You can see the mix in nomen's photo - great drainage, and it even looks good. You can go 'all the way' and use grit, pumice, scoria, perlite, turface - few of these mixed together would make mix similar to nomen's. If they are not available or difficult to source, at least get a bag of perlite and mix with some cactus&succulent soil in 50/50 ratio - I do not use this mix but many ppl do. I believe it would be improvement on existing soil. Watering 1/week sounds ok, but it could be misleading - all depends on the potting soil - if it contains too much peat, it likely stays wet for too long even if it looks dry on surface. Spraying established succulent isn't good idea IMO - spraying soil would be ok. Watering with can or bottle is much simpler. Plants should be watered thoroughly (that's where well draining mix works best) and then let dry out. It could be few days or longer in-between - depends on drainage and also temps (in ac home, it may take bit longer to dry out than outdoors). Watering in 'sips' & often is not recommended. I commented abo the foil since 'wrapping' pots with it, and also blocking the drainage hole would not be beneficial to any plant. But understand that some water protection was needed. If you need to protect furniture, any kind of saucer (nicer if it matching the pot) will work - plastic, terracotta. Just make sure that excess water doesn't sit there after watering - dump any out about 30min. after. If you don't have time to do that, pot could be raised (using plastic bottle caps, or vine corks or something similar) so excess water doesn't get re-absorbed back into soil, that would be too wet for succulents. Indoor lighting may be not enough, plant is slightly etiolated. Try to give it as much as possible, even supplemental lights may be needed. Not sure about proper ID, perhaps one of pachyverias or pachyphytums?