welcome High Voltage! i think i can answer a few of your questions.
1st .:
ADFs can pretty much be with most plants. however, when planning for plants, the things you really need to be concerned about are PH, temperature, light and nutrient compatabilty. i mean, it's not gonna work out if you have some plants that need alot of light, low temps, lots of nutrients, can only be partially submersed and high PH mixed with ADFs that need moderate temps and low to moderate light, middle-of-the-road PH just for example.
from experience and research, also have to be carefule about which plants are being sold in stores. i have found that many plants being sold as aquarium planting, fully submersed are actually not suited at all for aquariums. unless you're a pro at planted aquariums, it is really hard to keep these "false" aquarium plants alive, let alone thriving.
for example i was captured by the beauty of some Aluminum plant cuts i saw at the LFS. took them home only to find out i was duped. despite efforts, they died after 2 weeks. Aluminum plants are NOT to be fully submersed, it's a very pretty plant that grows in seasonal marshes. places that get flooded for short periods of time.
do alot of research. keeping an eye out for plants that will not only be compatible with your ADF's care requirements, but also match your level of care commitment and skill. not to forget visual appeal. try some of these sites, they were helpful to me, a newbie to aquarium planting. <img src="/images/graemlins/smile.gif" alt="" />
Aquatic Plant FAQs Aquarium Plants for the Student Bedget Light requirements for Aquatic Plants these are just a few to get an idea.
2nd .:
i would say for tank mates, again keep in mind compatibility to ADF car requirements, over stocking, species' general behavior and rule of thumb - if the frog fits, they will eat it.
3 .:
i have been seeing some forum posts about sand digestion and ADFs. alot of mixed opions and health concerns. since you're not new to ADFs, your familiar with their fedding techniques. they hunt, snapping mouth agaped. they have no tongues.
anyways, because of this method it is not uncommon that an ADF may accidentally snatch up a peppble or bit-O-sand. in the wild this too occurs and is passed through if bits are small enough. aware of this, some ADF owners use fine grain sand. seems to make sense to me, although there are many reports of sand digestion to also cause compaction problems resulting in death.
if you really would like to use sand as substrate for the plants, i might suggest a thin layer of pepples (or whatever) on top of the sand. remember to keep the size of pepples just large enough to not be easily swallowed, nor too large and deffinitely not sharp. ADF skin is fragile.
4 .:
heaters are great for ADFs since they prefer a comfy 76F - 80F temps. i have used both glass tube heater (adjustable temp control) and plastic/rubber encased (non adjustable) heaters with my ADF. my ADF preferred the glass one, as she would cozy up to the suction cups to sleep sometimes. generally i think most heaters are fine for ADFs, unless you've got unstable decorations that might break a glass tube heater. honestly, if you're really concerned about ADFs getting burned, i would go for a wire floor heater setup. it goes on the bottom of the tank before you add substrate. it is also observed that this sort of heater setup is greatly beneficial to plant root growth.
5 .:
for your question on behavior. i would suggest holding off adding ADFs until all plants are planted and tank has cycled. this gives the plants time to adjust, begin healthy growth and actively growing plants aid alot in the cycle process by absorbing nitrites/nitrates as nutrients. once the plants stabalize themselves they will also speed things up with oxygen production.
so, when everything has cycled, stabalized and growing nicely, you decide to slowly acclimate the ADFs... you should keep in mind that just like us, they have their own personalities. generally though, the first few days might be stressful for them so i would expect skittishness, loss of appetite and alot of hiding. it's been suggested to have at least one tank side a backdrop, helps to relax them and i wouldn't constantly peer into tank checking on them for 2 days.
after a few days to a week, i would expect the ADFs to be hungry and begin to feel safe in their new home. maybe they'll explore the new place, new tank mates, socialise and whatever else ADFs do.
other things i read that aid in ADF relaxation/stress relief are things like having tank location where there's no loud noise, frequent on/off of lights, heavy traffic (say a living/family room where parties or kids are frequent). i learned this myself, my poor ADF stopped greeting me and would hide almost all the time when i moved the tank from corner bar area to kitchen counter (counter seperated living room hub from kitchen).
deffinitely NO bumping or tapping the tank, even if you think one might be dead. keep hands out of tank for the first week while they adjust, amphibians have delicate systems and when stressed can easily get sick.
something else i recently read that i thought was cool. amphibians need colour. interestingly enough researchers/herpatology enthusists observed that amphibians need a multicoloured environment. too much of any one colour affects their emotional health. in some cases may lead to breeding problems as well as behaviors associated with anxiety disorders, depression and other such neurosies.
dunno, perhaps this is all part of the camoflauge they developed to better the chances of survival. so when in captivity a lack of colour/patterns creates stress, a kind of instinct to be aware that they stand out like a sore thumb. easy pickings for a predator. that's just my opion.
6 .:
i don't think live plants are a necessary. of course they're benificial, nicer, more "homey" for the tank, but many hobbyists use silk plants instead. what they deffinitely need are places to hide in when they feel insecure or ill, specially so if you're using a light. they also need shady spots, adequate (but gentle) air circulation and very clean environment.
and as for those price quotes for plants you mentioned, i think that's a serious rip off. you can find plants for as little as $2 in most major pet store chains. yes, they're not the best of quality but better than nothing.
hope all of this (yes, i knnow it's alot) helps you and others.
