Pretty darn ambitious (or masochistic)! Some thoughts though I'm sure you already know all this:
I thought Hasegawa kits were made so well that one didn't need putty (using the melt & squeeze method). I think Walmart has liquid plastic cement along with all the CA super glue types. If they don't have putty in the toy model section, head over to the automotive section and get some spot putty. Get the red stuff from the tube - it's similar to Squadron Green putty. There's Bondo too if you really need it.
Get sandpaper & paint from the toy, auto, or hardware depts.
Once you lay down your spray primer (I'd go with Testors Model Masters spray but it's more expensive), you can spray or brush paint. Testors spray or the little bottles will give you more colors but again, it's more expensive. The alternative is Krylon spray in the paint section.
Re: metal finish: IMO, if you're not spraying w/ an airbrush, I don't think it makes a difference what spray or brush-paint you use. IMO. I would still suggest a primer.
MechTech had a good point about warming up the spray can in warm water. Just a note, use warm water; do NOT use hot water. And if you haven't brush painted in a while, thin out the paints properly & practice a little.
Re: clear coats: use Testors Glosscote or Dullcote in spray or brush-on form, or that Krylon clear coat you found. If your store has the el-cheapo airbrush (Badger?), you can get a quart of Future acrylic floor wax; clean with Windex or an ammonia-based cleaner. You can also dip the canopy in it to get that ultra slick sheen. If you do, protect it from dust as it dries.
FYI - This is how I built what little I've actually built.
Just some thoughts. Looking forward to seeing the progress & end result! Good luck!