First, daylilies are not bulbs - they are fleshy-rooted perennials that are incredibly tough and hardy and can be planted anytime of year the soil is workable. Not all iris are bulbs either and many varieties can be planted similar to the daylilies. Most true bulbs that bloom in spring need a period of vernalization to set roots and develop flower buds, that's why they are planted in fall. If insufficient vernalization is provided, they won't bloom, or at least not that first season in the ground. The pre-chilling of spring flowering bulbs in warmer climates achieves the same purpose. IME, January is pretty much the limit on when one can plant spring flowering bulbs and expect them to bloom that spring. And that may be difficult to accomplish in zone 5.....I'd imagine your soils to be pretty well frozen at this time of year :-) The other aspect is that spring flowering bulbs available for sale this late in the planting season tend to be leftovers and of lesser quality....the good stuff's already been sold! One needs to maintain dormant bulbs under proper storage conditions for them to remain viable and they simply don't last forever out of the ground. If you don't have any bulbs on hand to plant now, I wouldn't recommend searching any out. The combination of unsuitable planting conditions (frozen soil or snowcover), the lack of quality bulb sources and the lateness of the season will just serve to produce unsatisfactory, frustrating results. Wait until later when the soil is workable and the weather cooperative to plant perennials like iris and daylilies. And look for already started bulbs (in containers in leaf and often in bud) available at garden centers or other plant outlets when they come in season - February and March in my climate, perhaps a bit later in yours. Or wait until fall to plant the dormant bulbs for the following spring. And pretty much any spring flowering bulb will work in your climate. You just need to do some research on what are bulbs (corms, tubers, etc.) and what are really rooted or rhizomatous perennials.

Berlin is much warmer than anywhere in Maine, but if you are lucky enough to have unfrozen ground then get them in quick. Even if there is a frozen crust, you could break through it to plant down where the soil hasn't frozen yet. It might be a good idea to mulch them if nights are very cold, just to stop the bulbs freezing before they can establish. If you just can't get them in the ground, pot them up and keep them somewhere that is either frost-free (but below 50F) or constantly below freezing but protected from the worst cold. Repeated freeze-thaw can damage potted bulbs and they can be killed temperatures that would be OK if they were six inches down in the ground. In spring you can bring them out for a nice display wherevere you want, even bury the pots in a bed if you want.

It might work--or not. I haven't ever put bulbs in mounds, so I don't know how they would withstand the rest of the winter. However, they do fine in sheltered areas in planters, so--if the mounds are high enough, they might be okay.

Daffs will do just fine, even if planted in late January [it's possible as long as the soil isn't frozen]. They'll just bloom a bit later than usual. Tulips may or may not do well because they want 30 to 50 "cold days" where the soil is below 36°F. If you have been keeping the bulbs in the refrig, you can add in that time when counting cold days. The variation in cold days required depends on the species. BTW, tulips look lovely, but rarely do well in our area due to the clay soil, as well as tulip-snacking squirrels. Improve your chances of success by planting the bulbs in soil which has been amended to be "light" (lots of perlite) or -a bit chancy but easier- plant the bulbs to sit on top of about 3" of coarse gravel with more gravel surrounding the bulb. I used aquarium gravel one year, and that seemed to do okay. 1"-inch wire mesh laid on top of the soil, under 2" mulch will deter most squirrels while permitting the plant to grow and bloom. BTW, in spite of the blustery winds, I've only counted 6 cold days since fall [central Fairfax County].