Oh, and i forgot to mention that the bubls were in a plastic bag(with some holes), and the plastic bag was in a paper bag. The bulbs were in that plastic bag during those 4 months

If your ground is not irretrievable frozen for now - plant them out now. You might need to pile old leaves over the top of the dahlias because they're like potatoes. They don't like being frosted. Expect to see them coming up in late May or early June.

The lilies (if they're asiatics) will be up soon and don't mind moderate frosts. Even the orientals (scented) are pretty tough. But they don't like being out of the ground for too long. Give them similar protection as you do for the dahlias if you know your garden is a bit of a frosty hollow.

They both appreciate at least half a day of sunshine and the dahlias don't mind westering sun.

They both appreciate being well-fed with compost and being in well-drained soil. No spring swamps, please.

Way too early to plant dahlias! These are summer blooming tubers that are typically planted out after last frost. They need warm soils to grow. In fact, unless these tubers were stored or remained somewhere above freezing during that 4 month unplanted period, they are most likely toast.

Check to see if both the lily bulb and the dahlia tubers are are still firm. Any softness generally means the bulb is beginning to rot and not worth planting. If they are still solid and firm and look good, you can plant them in containers now to be moved into the garden when temperatures warm.

Um. My dahlias live in the ground all year round. I get frosts to -5C and sometimes higher. The dahlia tubers are close to the surface and I give them zero special care over winter. They are fine and have flowered for more than ten years so far. (Which is not to say that a late frost won't swish early leaves. However, they will still recover and flower.)

I took into account that these tubers have been outside already - in a plastic baggie.

So it seemed reasonable to say - plant well and protect. My own experience with potting up dahlias to over-winter has been less than best and the inground ones, despite deluges of rain and frost, do much better in terms of growth and health.

And holding over the tubers often results in withered remains or early sprouts and slow root development.

Precautionary - possibly plant under the shelter of the house eaves, facing the sun and let the warmth from the house walls create a micro-climate. Attention to watering will be needed.

Pansy lover, what shape is the bulb and tubers in..are they soft, mushy, do the dahlia tubers have eyes.
If they are sill firm, then I'd say they are viable.
As to when to put them into the ground I yield to others who live in your zone 8...
Bulbs in warmer zones are given a cooling period before sale...then the ground gives them the rest of the cooling period required so they can gain roots. Yours, left out as they were, probably did not fare well..

Before planting, or before disposing of them, talk with your neighbors who have planted dahlia and lily, ask them when the optimum time to put them into the ground is.
It would seem to me NOW is the time..is it not January is planting time in the south....if not certainly February.