Group 1:
As much in Convert as you feel is necessary. I've only had one scenario in recent years where I actually had to ride the Convert timer, and that could have been negated with better DDs.
All remaining merits split between Ice (Paralyze) and Wind (Silence), with a preference for Wind since Paralyze II gets extra accuracy from its own merits.
Group 2:
Bio III - 1/5 at best, if it's a VW proc (not actually sure) and you still do that.
Dia III - 2/5 minimum, 3/5 for comfort, 5/5 can be nice (lasts 3 minutes with AF2+2 head augment).
Blind II - 1/5. 5/5 gains you -4 acc on the target and +8 m.acc. Additional reduction of accuracy is actually progressively better, however the increase per merit is tiny, and most current mobs have obscenely over-capped accuracy on players anyways, making its probable value nil.
Slow II - Haste is an exponential curve. That's to your benefit as you stack haste, but it has less and less value as you stack slow. Large amounts of slow (eg: Slow + Elegy) are still useful, but not so much with small amounts such as you get from additional merits. The only real value of extra merits is the extra m.acc.
Paralyze II - Paralyze proc rates appear to be a linear progression (ie: 5% paralyze paralyzes 5% of all attacks). From a defensive perspective, each additional percent is that much more valuable, since it's a damage reduction of 1/(100-N), where N is the current paralyze percentage. That is, from a damage reduction standpoint it works a bit like haste, where each additional percent is that much more valuable than the last. As such, I'd put as much into this as possible.
We don't have numbers for paralyze proc rates, however if it were the same as Slow II (35% at capped dStat, +1% per additional merit): Slow II from 1/5 to 5/5 is 3% slower attack speed; Paralyze II from 1/5 to 5/5 would be 6.5% fewer attacks. However, even if Paralyze II's base proc rate is much lower, it's still better. 10% to 14% is a 4.7% reduction in attacks.
Overall suggested distribution:
Dia III - 3/5
Paralyze II - 5/5
Slow II - 1/5
Blind II - 1/5
You can optionally pull one point from one of the others to bump Slow II up to 2/5.
Magic merits:
Enfeebling 8/8. It's what you're there for.
Optional:
Dark 8/8. If you're helping with stuns. In situations where free stunning isn't allowed, for mobs where the m.acc matters and you already have schs on stun duty, it may not be needed.
Enhancing 8/8. Even if you can get away with less on rdm itself, it's still useful for whm and sch.
Last 8/8 depends on what else you do, and what other jobs may want merits in the category (eg: blm, blu, smn, geo, etc). As such there's no single 'recommended' skill.