Given proper lighting you can grow a lot of "non-houseplants" indoors. Currently in that group I'm growing harlequin daisies, but some people grow tomatoes and peppers indoors. I've never actually grown pansies nor Portulaca, so I can't give you an suggestions there. As long as you can give your plants acceptable conditions they will be fine indoors, so I would advice researching what temperatures/humidity/other requirements your plants have.

I also can't advise you on the aphids :/

I have been having luck (so far) using a dilute peroxide mixture (1 part of 3% peroxide to 2 parts water for 1% peroxide solution) to combat fungus, bulb mites, and bulb scale mites. If you want to try peroxide you might spray the leaves of one of your plants with a dilute peroxide mix and see if it helps. (Though with the root-fungus and mites I have soaked the soil with the solution along with spraying and the plants don't seem to mind it -- just account for it in the watering schedule. I wouldn't think soaking would help with aphids though.)

Hopefully others with aphid experience can chime in with their battle plans :)

Happy growing,

Liltika

Pansies like it fairly cool, perhaps your lights are making it warm enough to stress the pansies (plus aphids like warmth).

I've tried starting portulaca from seed under lights, they get too floppy - they need way more light than artificials can give them.

I used to grow dwarf marigolds under lights - super easy, about 8 to 10 weeks from seed to bloom, even in the winter!