Retro MTB '88 Diamond Back Arrival Budget Build

First of all I'd like to introduce myself, this is my first 'proper' post, I'm mainly looking for somewhere to share my passion for bikes and builds and also for some advice from others as I go. And I enjoy drooling over the retro MTB builds. So, hi!

I recently bought an '88 Diamond Back Arrival frame with fork from eBay. It still has the original Tange Falcon headset, which seems okay, but I'll strip it down anyway as the grease doesn't look too clever.

I'm by no means a mechanic and very much doing this to learn as I go, any suggestions/advice is more than welcome.

So, the frame is aluminium and the fork is CRMO. Designed in USA and made in Japan. It was advertised as 'low mileage' - hard to tell. The paint is suffering some fairly bad, in places, blistering and bubbling. To be honest though, it was expected with a frame this old and doesn't bother me too much. I contemplated rattle can'ing a clear coat over it for protection but for what it'll be used for, I won't bother.

Definitely a budget build as I'm in need of a bike ASAP that will open up the trails/single track local to me and also a bike to commute on (when the apocalypse comes to an end... WFH). I only really have one bike in rideable condition at the moment which is a Specialized Tarmac - road riding is what I've been used to for most of my adult life but always have and always will look back with nostalgia and romanticise the steel MTB frames I rode as a kid in the 90s.

Anyway, I'm rambling. Lastly, I had initially planned on running this 1X9 as it's fairly hilly where I am and could have done with the range, but for now, I'll build it up as a single speed to get everything else dialled in before I start adding derailleurs.

Here is a list of parts that currently have or have incoming:

• Supacaz Grizips black lock-on grips
  
• Avid FR-5 levers
  
• 26" Malvestiti Vega 3000 rims laced to Shimano hub (rear) and generic hub (front)
  
• NOS MKS 2000 Grafight Pedals (old school BMX pedals?)
  
• 120mm NOS ITM Cromoly De Luxe quill stem
  
• Tranz X DH riser bars (Will eventually be replaced with XLC HB-C03)
  
• Shimano UN55 BB
  
• Acor Seat Post 25.4 (generic cheap eBay post, any suggestions for decent cheap 25.4 seat posts?)
  
• KMC Single Speed chain
  
• Sugino VP130 crankset 130BCD with Stronglight 38t chainring
  
• Schwalbe 26x2.25 Tough Tom (Hoping these clear - any reviews on these? Will eventually be replaced)
  
• Saddle will be pulled from another old bike until I can afford a nubuck Selle Italia Turbo or similar
  
  

Images from original seller apart from the catalog.

Cheers.