MOX13,
Hello and welcome to the forum. I'm glad to hear that you are doing some research first. Often we meet new enthusiasts under less than ideal circumstances and are sometimes put in the position of telling them that the tree they are seeking help with is already dead or dying. A little research up front will go a long way to helping to avoid an immediate disappointment.
I also like your idea of starting on two different levels. Very young/small material can be frustrating to work with as there is not a lot of training to be done, mostly simply growing out. Seedlings and cuttings are a good source of material but will take years of attention before much in the way of training can be done. Having something a little more advanced will serve several purposes. It will be more gratifying to have something that resembles the bonsai you see online, in books or in person. You will also have the opportunity to do some refinement and to learn some things in the process.
I understand that there is work involved with bonsai, but it seems to be something a little more easy to fulfill with a full time schedule.
The amount of work on any given day is minimal. Check the soil daily to see if the tree needs water and water if required. That's it! Fertilize the tree occasionally, re-pot once a year (at most) and you can get by for years like this. Perhaps a little pinching or light pruning as well but this is not terribly time consuming either.
This second tree I am lost as to where to start... A ficus seems like an easy choice, but I'm not as taken aesthetically by those trees as I am others such as the Japanese Red Maple. Alas, starting new I know I should start with an easier specie.
You have not stated if you intend to concentrate on growing indoors or outdoors. This has more than a little bearing on which species will be available to you. You mention that you are living in a house, not an apartment or dorm situation so I assume you can find a spot outside for a few trees if you wish. I move tender species outside for the summer and find the plants really respond well. Other species never see the inside of the house.
The ficus benjamina 'kiki' seems like a pretty cool product,
My experience with Ficus so far is still relegated to the growing out phase so this is 'book learnin'. Some sources note that F. benjamina don't back bud readily so the usual procedure of grow out and cut back is not easily accomplished with this species. I have seen some really nice F. neriifolia or Willow Leaf Fig as bonsai. the leaves are much more narrow and gives a different feel than other Ficus.
And junipers..... what's their story? Ive read at a few places they are easy, while other places say they are more difficult.
My experience with Juniper has been that they are relatively easy to care for. This in spite of the annual spate of Christmas Junipers that are doomed from the start. These 'bonsai' are marketed at the wrong time of year, in the wrong type of medium to people who don't understand their requirements. It is not surprising that most die. If you are interested in this species don't buy a commercially mass produced (mallsai) specimen. Instead go to a actual nursery and look at healthy trees of at least the one gallon size or larger and begin the training process yourself. They are not expensive, you will get much more tree for your money and will learn something about doing bonsai. A much better situation than buying an small stressed Juniper cutting and watching it die.
Let's say I purchase a "finished" bonsai..... I can still reform and practice such techniques as wiring on them, cant I?
Of course you can. The class of tree that you, as a new enthusiast, are likely to purchase as 'finished' will probably be a tree that, while it has had some training and a few years growing time, is still relatively young so more training would definitely be in order. Also, as kdodds noted, no bonsai, even a grand old masterpiece, is static so care/training never stops. It has been said that the only finished bonsai is a dead bonsai.
There are some good bonsai nurseries in the North-West that focus on yamadori (collected trees) when you decide to go looking for a more advanced piece of material.
I hope we have been of some help to you and look forward to seeing your efforts over the coming summer.
Norm