Before getting lost in the details of where to go and what stuff to buy...here are some pearls of wisdom.
Hiking teaches self reliance and self awareness (knowing thyself a little better: capabilities, limitations, what works for you and what doesn't)
Keep a log of hikes taken so people can see how many miles they have hiked cumulatively. Sometimes giving out awards for different mileage tiers can make the process fun and provide acknowledgement for the effort. Looking back over patches and milestones can be fun and can encourage others to try hiking.
Hiking is constantly evolving and never stays the same: mother nature makes the same trail look completely different time after time. Your abilities are always different with age and health. The group you hike with may change altering the dynamic. And I have never known a hiker who isn't constantly trying something new they bought or rearranging how they pack their bag to reduce weight.
When planning and taking hikes with kids, don't make a hike into a death march. If they don't have fun, they won't want to go on the next hike and the hobby won't become part of their life. Hiking will always make a memory that lasts a lifetime...make sure the memory is a positive one!
Know the ages and abilities of your group. Kids until about 15 to 16 years old usually don't like hiking because their bodies haven't caught up to their hormones. Usually once they hit 16 the mountain goat kicks in and you have to augment the lack of common sense. If you have a mixed age group the hardest challenge will be to make the hike enjoyable for everyone. This may not be possible in all cases and having family and advanced hikes may be worth considering. The most dangerous person on a group outing is always the adult who nostalgically remembers how they hiked as a 18 year old mountain goat and forgets that their equipment (gear and body) have aged. Adults have contributed to more of my trail issues and first aid opportunities over the years than any kid.
Beware the non-humble hiker
Trail etiquette: 1. Uphill hikers have the right of way.
2. On trail switchbacks, don't shortcut the turns causing increased erosion.
3. Yield the right of way to bicycles and horses.
Safety
1. Always use the buddy system (both to support any potential injuries or health responses). Isolated single hikers also make more appetizing targets for mountain lions and other potentially hungry wildlife. When hiking you have re-entered the food chain (not necessarily at the top).
2. Review the trail map with a compass before starting the hike to make sure each member of the group is familiar with the plan, basic compass bearings and can tell someone if needed where the cars are parked and what the group objective was. Your group is only as strong as the weakest link. The youngest child is just as important as the veteran adult in knowing the information.
3. Bracket your group on the trail with a responsible leader in front that knows how to keep the group together and set a steady pace, and a leader at the back that ensures no one gets left behind. Both leaders work together. A hike is not a race; everybody wins when everybody gets to the objective.
3. If you leave the trail to use the restroom, leave your backpack on the side of the trail so others know where to look for you if necessary.
4. If the hike is becoming too challenging for everyone in the group, call an audible and adjust the plan. Constantly observe your group to see signs of excessive struggle or health issues (Is someone walking with a limp to conceal a blister...when is the last time everyone took a drink of water...Is your group still together?).
5. Remember to look up and enjoy the scenery...and also to make sure the weather isn't doing anything unexpected.