So taller tanks are more likely to bow than shorter ones? Was looking at 8ftx3ft deep and maybe 2-2&/12 ft tall (don’t like square look)It will be hard to recommend a proper return pump without knowing the intended drain size + return size + overflow size although for my similarly sized system I went with 2 red dragon 230w flow models.
Frankly jebaos are likely fine if you want an inexpensive dc option or fluval sp for internal ac option
I've seen a large number of big tanks with tiny overflows and 3/4-1" bulkhead holes before which imo is far from ideal for any marine/reef setting. If this tank is being designed new at the very least I would suggest taking the time to plan out 2 return holes for the easier option of running 2 pumps (for redundancy) + utilizing 3 drain holes for at least 1.5" bulkheads (depending on intended return gph and overflow capacity)
For heating I would recommend multiple eheim jagers controlled by a ranco or aqualogic controller. It's a bullet proof combo bar the size of eheims heaters (a potential issue with your 48x20 sump foot print)
Skimmer wise I would simply recommend any that utilize a dc feed pump since you may change your filtration methods over time (socks to floss/roller fleece etc) which makes for a more consistently performing skimmer ime.
Lastly if your tank is going to be built entirely new I would also very strongly reccomend going with thicker acrylic to reduce any bowing (especially at 36" of height). The more the tank bows the easier it will be to scratch and a significant bow is very noticable and unsightly. The last thing I would want for you is to regret your purchase of a large tank.