please put some line breaks in that giant block of text. it will make it easier to read. use bullet points and remove some of the extraneous information to make it easier to answer your questions.
the "unsealed" bearings in headset are not difficult to service, so you would not be gaining much out of a new sealed-bearing headset other than keeping dirt and grime out with better seals. I recommend cleaning and repacking the bearings in the existing headset for now.
I'd have to confirm visually, but it looks like that bike takes a standard 1-1/8" threadless headset. it's not "tapered" so you don't have to worry about that. there are so many options out there, I don't know where to start.
does your bike have a brake that grabs the rim (a v-brake aka linear pull brake) or a brake near the hub that grabs a disc (disc brake). I looked up that model, and it appears to come with rim brakes. just about any "v-brake" should fit and work on your bike.
for the fork (not forks, because there's only one fork on your bike), you need something with a "straight steerer tube" (not tapered), something that is designed for a 26" wheel, and posts to mount a linear-pull rim brake, aka v-brake. 100mm of travel would suffice and I can't recommend going much longer than that. something that works with a standard quick-release axle (not any sort of "thru-axle") would be necessary as well. there are not a lot of options on the market for a good suspension fork, but they still exist. another option is a rigid fork. it does not sound like you're making full use of rowdy trails with drops and jumps, so a rigid fork might save you a lot of hassle and money.
it sound like you are talking about the headset, which includes the bearing cups that press into the frame, the bearings, the crown race, and the upper bearing cone/wedge assembly. you just need a new headset. the crown race is always part of the headset, so it would have replaceable. (there are some more obscure standards for a fork that has a built-in crown race, but that certainly not the case on your bike.) it's very unlikely that you can just replace the bearings with sealed units, as the cups in the frame are rounded inside and shaped to hold round balls.
the "unsealed" bearings in headset are not difficult to service, so you would not be gaining much out of a new sealed-bearing headset other than keeping dirt and grime out with better seals. I recommend cleaning and repacking the bearings in the existing headset for now.
I'd have to confirm visually, but it looks like that bike takes a standard 1-1/8" threadless headset. it's not "tapered" so you don't have to worry about that. there are so many options out there, I don't know where to start.
does your bike have a brake that grabs the rim (a v-brake aka linear pull brake) or a brake near the hub that grabs a disc (disc brake). I looked up that model, and it appears to come with rim brakes. just about any "v-brake" should fit and work on your bike.
for the fork (not forks, because there's only one fork on your bike), you need something with a "straight steerer tube" (not tapered), something that is designed for a 26" wheel, and posts to mount a linear-pull rim brake, aka v-brake. 100mm of travel would suffice and I can't recommend going much longer than that. something that works with a standard quick-release axle (not any sort of "thru-axle") would be necessary as well. there are not a lot of options on the market for a good suspension fork, but they still exist. another option is a rigid fork. it does not sound like you're making full use of rowdy trails with drops and jumps, so a rigid fork might save you a lot of hassle and money.