they would be fine as 2 females,
But seriously do your research before buying any of the fish,
Consider their mature size, what their swimming habits are,
and do you know about cycling your tank?
Personally in a small tank like yours I would only consider having a vary of tetra species or some guppies one sex only else you will have heck loads of babies.
and if you want an algae eater only one because of the tank and the amount of algae it could have,
unless your prepared to feed vegetables like,
cucumber lettuce etc..
if you stock how you plan on you will have very unhappy and dead fish,
Imagine living in a small room all your life using the space as your toilet (floor)
now add a few more people thats not healthy