Betta buddies and my live plants

Hey all, I'm fairly new to all of this.

Last semester, without really knowing too much of what I was doing, my girlfriend and I bought male VT bettas. Knowing that the cups weren't the best things for them, we both bought slightly larger (1 qt) containers. She then splurged and went all out with 2.5's (two because she bought a female betta to keep in a second tank when she bought this stuff) with silk plants, heaters, covers, the works.

In light of that, I have an eclipse hex 5 that my parents got me for my betta. I've got a few live plants in there, a Peacock fern (Selaginella wildenowii), wisteria (Hygrophilia difformis) and an umbrella plant (Spathiphyllum wallsii). My parents got all that for me for christmas so my betta wouldn't be confined to the 1 qt container that I'd been meaning to upgrade here. I've got a couple questions concerning this whole thing.

First of all, would it be a good idea or at least workable to get a pleco, catfish, or other to help control the algae population in the tank? Generally speaking, would it be alright in that size a tank with the consideration of the live plants and all? I've heard both sides, that the plant-eater will terrorize my plants or keep conditions healthy for them. There's a filter and light built into the hood which is nice for having everything in one place. The small currents created by the draw seems to amuse my betta (Marcus) quite a bit...he'll take a breath, swim to where the filter flows into the surface of the water and ride the current down and around the tank.

Another question there arises: I've made sure through the clever use of my peacock ferns and umbrella plants that there's a good chunk of the tank where the currents are incredibly weak, as I've heard that currents too strong can stress bettas. Would it be alright to put a small ornament in there to help with that? I would do so anyway if I had a pleco or catfish so they would have somewhere to go, but would it be prudent to put in something for my betta? If so, what would work?

I've read about using short lengths of PVC piping, small, clean terra cotta pots and such, and don't really want to use a lot of the pet store ones for fear his fins will be caught or ripped on them. What would be a good choice?

Secondly, the lower leaves on the peacock fern are dying off. It just seems that that's from the light of the tank being considerably stronger at the top and shading the lower leaves from getting too much light. The stems, roots, and upper leaves are looking just fine, and I'll probably thin them out a bit.

The wisteria's not looking too hot. It was fairly cool where my parents kept the plants before they gave them to me, so I figured that they'd recover alright once I put them into my tank. They were fairly brown with good roots and stems when I put them in and seem to be budding and greening up a little more. Is there anything I could use to help that recover? would aquarium fertilizer help and not be detrimental to my fish?

I really would like to get another fish or something else to put in the tank, maybe a ghost shrimp or dwarf frog I've heard would make good tank buddies. Would that then also be compatible with a pleco and whatnot, though? I'm an anally retentive engineering major, not used to this many variables ;-) Marcus seems fairly docile, even when I put a mirror up, he flares and then swims to the other end of the tank. *shrug* Any and all input would be appreciated Thanks!