You say it's about "...general concepts rather than specifics..." but all of the questions you ask following that require knowledge of the specifics. The answers depend on the size, shape, layout and what other things/plants exist within the space. The "rule" about planting in odd numbers probably wouldn't apply because the numbers would be so high that nobody's counting, or could count. It would be numbers like: 25 to 300, or even larger if your yard is large.

For greater impact with bulbs, plant the bulbs in groups. Don't worry about the odd/even number thing, think 10-15 or more in a group at minimum. Don't worry about balancing allium, tulips and daffs: they all bloom at different times.
Because bulbs come up before most other plants develop foliage, its usually better to use a repeating pattern of groups throughout the garden or landscape. You could also plant a "ribbon" of bulbs or a larger grouping.

Thanks for the tips and sharing some ideas in how to designing with bulbs..

I agree with planting the bulbs in large groups or even mass "waves". You could also inter plant them with perennials and layer them so they get multiple bloom periods before there foliage is covered by up coming perennials such as Hosta's or daylily.

Here is a link that might be useful: Spring bulbs for long bloom period

So I should plant all the tulips in one mass and all the daffs in another etc? Or should I make a grouping of daffs, tulips etc and then repeat the combination around the yard?

Again, without the specifics, it's going to be difficult for you to get good advice. No one knows how many "all the tulips" is. If your yard is palatial, a half-dozen square feet of anything will look like a drop in the bucket. If the yard is small, it could be enough to look like something. Things need to look balanced and coordinated.

The internet is a great resource and I recommend googling images of spring bulbs. Copy the look you want. So much depends on how many bulbs, what type, other perennials and shrubs you have, and your personal preferences.

I prefer to see spring bulbs in drifts rather than little clumps here and there, but the latter can be effective when they are planted near certain types of perennials or shrubs.

Keep in mind that bulbs will multiply. Also the dying foliage must be retained for bulb health so it's best to plant bulbs with or behind other emerging perennial foliage that will hide that.

Years of design experience has led me to designating the daffodil and tulip families as "flash in the pan" blossoms. Beloved, beautiful when in bloom. A pain in the neck after their big show waiting for foliage to die back.

On large properties I always look for a spot which can be viewed from the entrances, preferably under and extending from the drip edge of a mature deciduous tree, that can be designated a short term 'natural' area. Here daffodils are planted in quantity, grass remains uncut until bulb foliage dies. No tree available? Nothing wrong with working such a plan somewhere on lawn edge, etc.

Generally large displays of tulips are considered annuals to be dug and tossed after blooming unless one can hide the dying foliage behind dense emerging perennials such as peonies. I enjoy using them as annuals, trying different spots/big pots about the property rather than being restricted by their regimentation year after year. It's OK to allow yourself the time to play in the garden with different ideas.

The back yard is about 85' x 100' which is why I am worried about it looking spotty. There is a play ground, firepit with apple tree and a pool along the left side, poolhouse, butternut tree along the back, driving tent, another apple tree, garage and parking pad on the right side, deck along the house. Flower beds line all sides. I have a lot of perennials and shrubs but still a lot of blank space and I don't really know where to put these to best advantage.I have already put clumps in the garden that surrounds my firepit and the gardens under the apple trees. I can't plant along the back because we are in a property dispute.

When you have a large area to fill with bulbs, it's often attractive to plant them in drifts, as mentioned above, so they look natural. As for types of bulbs to plant, you might take a look at Brent and Becky's Bulbs catalog. Their catalog has good descriptions to help you figure out what might work in your climate.
As for "pop," I'm a huge fan of allium.

Here is a link that might be useful: Brent and Becky's Bulbs